CN110579724A - A multi-channel pulse-pumped atomic magnetic sensing device - Google Patents

Abstract

The invention discloses a multi-channel pulse-pumped atomic magnetic sensing device, which comprises at least one spectroscopic polarization-maintaining transmission system; at least one pump light; The polarized light; the atomic magnetic sensing module that is connected to the spectroscopic polarization-maintaining transmission system and receives the detection light. The spectroscopic and polarized-maintaining transmission system includes a depolarization module, a spectroscopic module and a polarizing module. The depolarization module and the spectroscopic module are connected and Set before the polarizing module. The advantage is that the laser is divided into required multi-channel lasers by first depolarizing, then depolarizing and then polarizing, or first depolarizing, then depolarizing, and then polarizing. The polarization causes the atoms to generate a large macroscopic magnetic moment, which satisfies the condition that multiple probes share an atomic gas chamber for multi-point information measurement, and improves the efficiency of information measurement.

Description

A multi-channel pulse-pumped atomic magnetic sensing device

technical field

The invention relates to the field of atomic magnetometers, in particular to a multi-channel pulse-pumped atomic magnetic force sensing device.

Background technique

Magnetic field information exists in many occasions, and many unknown information can be obtained by using magnetic field information, which has many applications in geomagnetic detection, biological magnetic field detection and so on. Classical magnetic field measuring instruments include fluxgate, Gauss meter and other devices. With the mature development of quantum measurement technology, atomic magnetometers based on quantum effects have appeared, mainly including optically pumped magnetometers, proton magnetometers, spin-exchange-free relaxation magnetometers, and pulse-pumped magnetometers. The atomic magnetometer has higher sensitivity and accuracy, and is the current mainstream development direction of magnetic field measurement instruments.

However, most of the existing atomic magnetometers are single-channel technical solutions, that is, only one probe light is passed through a single atomic gas chamber, and the probe light interacts with the atoms to generate signals, and then receives the magnetic field information through the corresponding photoelectric sensing device. The single-channel technical solution can only measure the information of a single point in the atomic gas chamber, resulting in low efficiency of information measurement.

The main difficulties in realizing a multi-channel atomic magnetic sensing device are: 1. The existing multi-channel technology for a single atomic gas cell has defects, and the distance between adjacent detection lights must be greater than the diffusion length of the atoms to ensure that different detection light effects can be achieved. It is different atoms, and different signals are detected; 2. The multi-channel atomic magnetic sensing device must be equipped with multiple laser beams as the detection light, and the lasers that emit the required lasers are expensive. Increasing the cost of the entire sensing device is not conducive to commercial promotion. However, the existing spectroscopic methods, such as the use of a beam splitter or an optical beam splitter, have the disadvantage that a relatively complex splitting system needs to be built, and each lens needs to be precisely adjusted, and the system is easily affected by vibration; The optical fiber splitter performs light splitting, but since the laser is a coherent light source with good polarization, the polarization of the laser after splitting by the optical fiber splitter is poor. The atomic magnetic sensing device requires the detection light to be polarized light, and the optical power Basically the same, therefore, the multi-beam laser that can be split only by the fiber splitter cannot meet the working requirements of the atomic magnetic sensing device.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a multi-channel pulse-pumped atomic magnetic sensing device, which can realize the optical path polarization-maintaining spectroscopy and the density problem of the optical path channels in the atomic gas chamber, and eliminate the problem of the density of the optical path between different channels. The mutual interference of the pump light is realized, the optical path sharing of the pump light is realized, the information measurement efficiency is improved, the number of lasers is reduced, and the cost is greatly reduced.

The purpose of the present invention adopts following technical scheme to realize:

A multi-channel pulse-pumped atomic magnetic sensing device, comprising:

at least one spectroscopic polarization-maintaining transmission system;

At least one pump light;

multi-channel detection light, the detection light includes polarized light obtained by splitting through a light-splitting polarization-maintaining transmission system;

an atomic magnetic force sensing module that is connected to the spectroscopic polarization-maintaining transmission system and receives the probe light;

The atomic magnetic force sensing module includes at least one row of atomic gas chambers arranged in sequence, and a photoelectric sensing device corresponding to the number of detection lights, wherein each atomic gas chamber is passed through at least one of the detection lights, and passes through the detection light. The spacing of the probe light in the same atomic gas chamber is greater than the diffusion length of atoms under a certain temperature and a certain buffer gas pressure, and the photoelectric sensing device is arranged on the side where the probe light exits the atomic gas chamber, and is used for receiving signals generated by the interaction of the probe light with atoms, the pump light passing through all the atomic gas cells on the same column;

The spectroscopic polarization-maintaining transmission system includes a depolarization module for converting the laser light into completely unpolarized light, a light splitting module, and a polarization module for converting the laser light that has become completely unpolarized light into polarized light, the depolarization module. The polarizing module is connected to the light splitting module and is arranged before the polarizing module.

Further, the optical splitting module includes an optical fiber splitter, an optical fiber coupler is connected before the optical fiber splitter, and an optical fiber collimator is arranged after the optical fiber collimator, and the optical fiber collimator is arranged before the polarization module.

Further, the depolarization module is a depolarizer, which is arranged before the optical fiber splitter or after the optical fiber collimator.

Further, the depolarization module is a large-core-diameter multimode fiber with a certain length, which is connected to the optical fiber splitter and is arranged between the optical fiber splitter and the optical fiber collimator.

Further, the optical splitting module includes multiple stages of the optical fiber splitter, and the optical fiber coupler is connected to the first-stage optical fiber splitter.

Further, the optical splitting module includes an optical splitting device, and the optical fiber coupler is arranged between the optical optical splitting device and the multi-stage optical fiber splitter.

Further, the atomic gas chambers are sequentially arranged on the same straight line.

Further, the probe light is perpendicular to the surface of the atomic gas cell and the pump light at the same time.

Preferably, the multi-channel pulse-pumped atomic magnetic sensing device includes at least one plane mirror, and the plane mirror is arranged on the side where the pump light exits the atomic gas chamber, and is used to reflect the pump light Return along the original path to improve the pumping efficiency.

Further, the pump light includes polarized light obtained by splitting through another light splitting polarization maintaining transmission system.

Compared with the prior art, the beneficial effects of the present invention are:

(1) Divide the laser into the required number of multiple lasers by first splitting, then depolarizing, then polarizing or first depolarizing, then splitting and then polarizing. The power of each laser is roughly equal, and they are all polarized light. This polarized light can be used as probe light or pump light.

(2) The atoms are polarized by injecting the pump light into the atomic gas chamber, so that the atoms generate a large macroscopic magnetic moment. At least one way of detection light is set to pass through an atomic gas chamber to form at least one channel, and the distance between the detection lights passing through the same atomic gas chamber is greater than the diffusion length of atoms at a certain temperature and a certain buffer gas pressure, which satisfies many requirements. The condition of multi-point information measurement is carried out by using the same atomic gas chamber for the detection light of all paths, which improves the efficiency of information measurement;

(3) A channel in the atomic gas chamber refers to a channel of detection light passing through the atomic gas chamber, the detection light interacts with the atoms to generate signals, and receives signals through the corresponding photoelectric induction device, and the detection light corresponds to a photoelectric induction device, The photoelectric sensing device is used to receive the signal generated by the interaction between the probe light and the atoms, so that the system can obtain the detected magnetic field information.

Description of drawings

Fig. 1 is the overall frame structure diagram of the embodiment of the present invention;

FIG. 2 is a schematic diagram of a frame structure of an embodiment of a spectroscopic polarization-maintaining transmission system of the present invention, which shows a frame structure of first depolarization and then splitting and then polarizing using a depolarizer;

3 is a schematic diagram of a frame structure of another embodiment of the spectroscopic polarization-maintaining transmission system of the present invention, which shows a frame structure that uses a depolarizer to first split, then depolarize, and then polarize;

FIG. 4 is a schematic diagram of a frame structure of another embodiment of the spectroscopic polarization-maintaining transmission system of the present invention, which shows a frame structure of a large-core-diameter multimode fiber that is firstly split, then depolarized, and then polarized;

5 is a schematic structural diagram of a spectroscopic module of an embodiment of the spectroscopic polarization-maintaining transmission system of the present invention;

6 is a schematic structural diagram of a spectroscopic module of another embodiment of the spectroscopic polarization-maintaining transmission system of the present invention;

7 is a schematic structural diagram of an optical spectroscopic device of the present invention;

8 is a schematic diagram of the principle structure of the pulse-pumped atomic magnetic sensing module of the present invention;

FIG. 9 is a schematic configuration diagram of a preferred embodiment of the atomic gas cell of the present invention, which shows that a single atomic gas cell is injected into the multiplexed probe light;

Figure 10 is a schematic diagram of another configuration of another preferred embodiment of an atomic gas cell according to the present invention, showing the arrangement of a single row of atomic gas cells;

FIG. 11 is a schematic diagram of another configuration of another preferred embodiment of an atomic gas cell according to the present invention, which shows the arrangement of a plurality of columns of atomic gas cells;

In the picture:

10, laser; 11, laser; 12, optical fiber; 13, completely unpolarized light; 14, fiber coupler; 15, fiber collimator;

20. Spectral polarization maintaining transmission system; 21, depolarization module; 211, depolarizer; 212, large core diameter multimode fiber; 22, optical splitting module; 221, multimode fiber; 222, optical splitting device; 23, polarizing module;

30. Pump light; 31. One-half wave plate; 32. One-quarter wave plate;

40. Probe light; 41. One-half wave plate;

50, atomic magnetic force sensing module; 51, atomic gas chamber; 52, photoelectric induction device; 53, temperature control device; 54, static magnetic field; 55, alternating magnetic field; 56, magnetic force signal; 57, plane mirror.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that, on the premise of no conflict, the embodiments or technical features described below can be combined arbitrarily to form new embodiments. .

The following description serves to disclose the invention to enable those skilled in the art to practice the invention. The preferred embodiments described below are given by way of example only, and other obvious modifications will occur to those skilled in the art. The basic principles of the invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions without departing from the spirit and scope of the invention.

It should be understood by those skilled in the art that in the disclosure of the present invention, the terms "portrait", "horizontal", "upper", "lower", "front", "rear", "left", "right", " The orientation or positional relationship indicated by vertical, horizontal, top, bottom, inner, outer, etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and to simplify the description, rather than to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and thus the above terms should not be construed as limiting the invention.

It should be understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be one. The number may be plural, and the term "one" should not be understood as a limitation on the number.

In the present invention, unless otherwise expressly specified and limited, the terms "assembled", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated It can be connected to the ground; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two components can be connected internally. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

1 to 11 , a multi-channel pulse-pumped atomic magnetic sensing device according to an embodiment of the present invention will be clarified in the following description, wherein the spectroscopic polarization-maintaining transmission system 20 solves the existing multi-channel detection technology The problem of using multiple lasers in the process greatly reduces the cost, so that each laser can meet the detection requirements of the atomic magnetic sensing equipment, and the atomic magnetic sensing module 50 solves the density problem of the optical path and excludes the same atomic gas chamber. Mutual interference between different channels improves the measurement efficiency of information.

It can be known from the prior art that the pulsed pump magnetometer needs two beams of light, one of which is circularly polarized pump light to generate a macroscopic magnetic moment precessing along the Z direction. The atomic gas chamber is used to polarize the atoms, and the time required is very short, and it is turned off during the detection process so as not to interfere with the detection light; a beam of linearly polarized detection light. In the pulse-pumped magnetometer, the rotation of the magnetic moment is detected, and the projection of the rotation of the magnetic moment is on the XOY plane. Since the projections of each atom on the XOY plane are not consistent, radio frequency π/2 pulses can be added to X or Y. The function of the π/2 pulse is to adjust the projection of all atomic magnetic moments in the XOY plane to the direction consistent with the direction of the radio frequency, and adjust the rotation plane of the magnetic moment to the XOY plane. When the atomic magnetic moment is at the maximum in the XOY plane, The polarization of the linearly polarized probe light is modulated by the atoms, and the polarization is rotated. The frequency of the rotation is the Larmor precession frequency of the atoms rotating around the Z axis. The rotation of the polarization can be detected by an analyzer or a polarization beam splitter.

As shown in FIG. 1, which shows a multi-channel pulse-pumped atomic magnetic sensor according to an embodiment of the present invention, which includes

at least one spectroscopic polarization maintaining transmission system 20;

At least one pump light 30;

multi-channel detection light 40, the detection light 40 includes polarized light obtained by splitting through a polarization-maintaining transmission system 20;

an atomic magnetic force sensing module 50 that is connected to the spectroscopic polarization-maintaining transmission system 20 and receives the detection light 40;

The atomic magnetic sensing module 50 includes at least one row of atomic gas chambers 51 arranged in sequence, and photoelectric sensing devices 52 corresponding to the number of detection lights 40 , wherein each atomic gas chamber 51 is passed through at least one detection light 40 , passing through The distance between the probe light 40 of the same atomic gas cell 51 is greater than the diffusion length of the atom at a certain temperature and a certain buffer gas pressure. The magnetic signal 56 generated by the interaction, the pump light 30 passes through all the atomic gas cells 51 on the same column;

The spectroscopic polarization-maintaining transmission system 20 includes a depolarization module 21 for converting laser light into completely unpolarized light 13, a light splitting module 22, and a polarization module 23 for converting laser light into completely unpolarized light 13 into polarized light , the depolarization module 21 and the light splitting module 22 are connected and arranged before the polarizing module 23 .

One atomic gas cell 51 in the atomic magnetic sensing module 50 needs two lasers with different frequencies, that is, one is the probe light 40 and the other is the pump light 30, so the system needs at least two lasers 11 and two spectroscopic polarization maintaining The transmission system 20, as shown in FIG. 1, is two lasers 11 and two polarization-maintaining transmission systems 20. The probe light 40 and the pumping light 30 are respectively divided into several paths by the polarization-maintaining transmission system 20, which are perpendicular to each other. , passing through the atomic gas chamber 51 . It should be noted that the number of the lasers 11 and the spectroscopic polarization-maintaining transmission systems 20 is not limited in this embodiment. Optionally, the number of the lasers 11 and the spectroscopic polarization-maintaining transmission systems 20 in this preferred embodiment can also be 3 , 4, 5, 6, 7, 8, etc.

In the embodiment of the device, the laser is divided into a required number of multi-path lasers by performing first depolarization, then depolarization, and then polarization treatment, or first depolarization, then depolarization, and then polarization treatment. The polarized light can be used as probe light 40 or pump light 30, each probe light 40 corresponds to a photoelectric sensing device 52, and multiple probe lights 40 can realize the detection and transmission of atomic state information at different positions, and improve the detection efficiency; , the pump light 30 is injected into the atomic gas chamber 51 to polarize the atoms, so that the atoms generate a larger macroscopic magnetic moment. In addition, a channel in the atomic gas chamber 51 refers to a channel of the detection light 40 passing through the atomic gas chamber 51, the detection light 40 interacts with the atoms to generate signals, and receives the signals through the corresponding photoelectric sensing device 52, and the detection light 40 corresponds to one channel A photoelectric induction device 52, the photoelectric induction device 52 is used for receiving the magnetic force signal 56 generated by the interaction between the probe light 40 and the atoms, so that the system can obtain the detected magnetic field information. The detection light of the pulse-pumped atomic magnetic sensing device needs to measure the polarization angle. Therefore, the photoelectric sensing device includes a beam splitter and two photodetectors. After the detection light passes through the atomic gas chamber, it is divided into Two orthogonal beams of light, two beams of light are respectively incident into two photodetectors.

The probe light 40 is polarized light that is split by a light-splitting polarization-maintaining transmission system 20 , the pump light 30 is polarized light that is split by another light-splitting polarization-maintaining transmission system 20 , and each atomic gas cell 51 is subjected to at least one probe light 40 . Passing through, the pump light 30 passes through all the atomic gas cells 51 on the same column. As shown in FIG. 8 , the core of the atomic magnetic sensing module 50 is a sealed atomic gas chamber 51 , which is filled with sufficient saturated alkali metal gas and buffer gas with a certain pressure. The atomic gas chamber 51 needs a temperature control device 53 to maintain a constant high temperature, so that the alkali metal saturated vapor can maintain a stable and high concentration; in addition, a static magnetic field 54 and an alternating magnetic field 55 are required, both of which can be Generated by Helmholtz coils. The pump light 30 forms a beam of parallel circularly polarized light through the half-wave plate 31 and the quarter-wave plate 32, and enters the atomic gas chamber 51 as the pump light 30 to excite the alkali metal atoms, while the probe light 40 passes through the atomic gas chamber 51. The half-wave plate 41 forms a beam of parallel linearly polarized light, which enters the atomic gas chamber 51 as the probe light 40 .

The components of the present invention will now be described in detail. The temperature control device 53 , the static magnetic field 54 and the alternating magnetic field 55 are in the prior art, and therefore will not be described in detail.

The laser is polarized light. As for how to realize the splitting of the polarized light and the polarization-maintaining transmission, this embodiment adopts the method of depolarizing the laser first and then polarizing it. After depolarization, the light is split and then polarized, the laser is first turned into completely unpolarized light 13, and then the completely unpolarized light 13 is transformed into linearly polarized light by the polarizing module 23 to reduce power loss for subsequent systems. Before or after becoming completely unpolarized light 13, divide it into the required number of multiplexed lights, and then convert it into polarized light before use, so that the power of each laser used is roughly equal, and all are polarized Light. Regardless of whether the splitting is performed first or the depolarization is performed first, before the end of transmission, the laser light can be converted into completely unpolarized light 13 and polarized to become polarized light.

In order to reduce the volume of the entire spectroscopic polarization-maintaining transmission system 20, the spectroscopic module 22 in this embodiment includes an optical fiber splitter 221. Compared with the traditional spectroscopic mirror or optical beam splitter, the optical splitting system is relatively simple. As for the splitter 221, it is obvious that in this embodiment, the optical fiber 12 is used to connect from the optical fiber splitter 221 to the optical fiber collimator 15, which is beneficial to reduce the size of the equipment and the complexity of the system. The types of optical fibers generally include single-mode fibers and multi-mode fibers, and single-mode fibers include polarization-maintaining single-mode fibers and non-polarization-maintaining single-mode fibers. In some systems that require laser polarization characteristics, polarization-maintaining single-mode fibers will be used. The stability of this kind of fiber is relatively good, and the polarization characteristics of the laser can be well maintained during the laser transmission process, but the disadvantage is that the light transmission efficiency of this kind of fiber is weak, which is easy to cause laser energy loss, and it is difficult to use. , the price is expensive; there are also some systems that use multi-mode fiber, which has high optical efficiency and is relatively simple to use, but the stability is not as good as that of polarization-maintaining single-mode fiber, which easily disturbs the polarization of the laser. In order to make the laser light enter the optical fiber splitter 221, the optical fiber coupler 14 is connected before the optical fiber splitter 221, and before the probe light 40 or the pump light 30 enters the atomic magnetic sensing module 50, it needs to be converted into space free light, so , the optical fiber collimator 15 is connected after the optical fiber splitter 221 , and at the same time, the optical fiber collimator 15 is arranged before the polarization module 23 .

Since the laser light passing through the fiber optic splitter is partially polarized light, its polarization direction is uncertain, and the polarizing module 23 cannot be directly used to convert it into linearly polarized light, which easily loses the laser power greatly and makes the laser unusable. Therefore, the polarization-maintaining transmission system 20 of the present embodiment converts the laser light into completely unpolarized light 13 by firstly splitting, then depolarizing, and then polarizing the laser light, or firstly depolarizing and then splitting and then polarizing the laser light, and then using the polarization module 23 Convert the fully unpolarized light 13 into linearly polarized light to reduce power loss for subsequent systems. Before or after converting the laser into fully unpolarized light 13, divide it into the required number of multiplexed lights, and then Turn it into polarized light before use, so that the power of each laser used is roughly equal, and all are polarized light. Regardless of whether the splitting is performed first or the depolarization is performed first, before the end of transmission, the laser light can be converted into completely unpolarized light 13 and polarized to become polarized light. The polarizing module 23 in this embodiment can use a polarizing beam splitter, and the completely unpolarized light 13 is divided into horizontal polarized light and vertical polarized light by the polarizing beam splitter, and the powers of the two beams are exactly the same. The laser 11 in the present invention refers to a device capable of emitting laser light in a broad sense, and the entire processing process starts from the laser 11 generating the laser, rather than from the laser emitting device. In reality, the output interface of some laser emitting devices is an optical fiber, which is built into the fiber coupler 14. During the application process, when depolarizing, splitting, and then polarizing, it is necessary to connect the output interface of the laser emitting device. The fiber collimator 15, The laser light is exported, depolarized by the depolarization module 21, and then introduced into the fiber splitter 221 through another fiber coupler 14 for light splitting; when the first light splitting, depolarizing and then polarizing process is performed, the laser emitting device is directly depolarized. The output interface is connected to the optical fiber splitter 221 for light splitting. The optical fiber coupler 14 described in the present invention is the optical fiber coupler 14 built in the laser emitting device.

As shown in FIGS. 2 and 3 , a configuration structure of the depolarization module 21 is that the depolarization module 21 is a depolarizer 211 , which is arranged before the fiber splitter 221 or after the fiber collimator 15 . It should be noted that since the optical splitter module 22 includes a fiber splitter 221, and the depolarizer 211 and the polarizer are both optical components, it is necessary to set the fiber coupler 14 and the fiber collimator 15. The laser light also needs to enter the fiber splitter 221 through the fiber coupler 14 .

More specifically, as shown in FIG. 2 , which is a schematic structural diagram of a system that performs depolarization first and then light splitting, the depolarization module 21 is a depolarizer 211 , which is arranged before the fiber splitter 221 , and the laser passes through the depolarizer 211 . Then, it becomes completely unpolarized light 13 , and is then divided into multi-path light by the light splitting module 22 , which is first depolarized and then split. More specifically, in an embodiment of the structure in which the depolarization is performed first, the light is split and then polarized, the laser light emitted by the laser 11 first undergoes polarization disturbance through the depolarizer 211, and becomes the completely unpolarized light 13, which is completely unpolarized light. 13 enters the fiber splitter 221 through the fiber coupler 14, and is divided into multiple paths of light. Each path of laser light is transmitted to the fiber collimator 15 through the fiber. It is linearly polarized light, and the polarizing module 23 is a polarizing beam splitter. The completely unpolarized light 13 is divided into horizontal polarized light and vertical polarized light by the polarizing beam splitter, and the powers of the two beams are exactly the same.

As shown in FIG. 3 , it is a schematic structural diagram of a system that performs light splitting first and then depolarization. The depolarization module 21 is a depolarizer 211 , which is arranged after the fiber collimator 15 . , each light is processed by the depolarizer 211 to become completely unpolarized light 13, which is firstly split and then depolarized. More specifically, in an embodiment of a structure that performs light splitting, depolarization and then polarization processing, the laser light enters the fiber splitter 221 through the fiber coupler 14, and is divided into multiple laser beams, and then each laser beam is transmitted to the optical fiber splitter 221 separately. The fiber collimator 15, the fiber collimator 15 is connected with the depolarizer 211, the laser light emitted from the fiber collimator 15 becomes completely unpolarized light 13, and the polarization module 23 after the depolarizer 211 then The completely unpolarized light 13 becomes linearly polarized light, the polarizing module 23 is a polarization beam splitter, and the completely unpolarized light 13 is divided into horizontally polarized light and vertically polarized light by the polarization beam splitter, and the power of the two beams is exactly the same .

Since the larger the core diameter of the fiber, the more modes transmitted inside the fiber, the higher the coupling efficiency of the laser, but the more disordered the polarization of the laser. Disturbance, the laser light transmitted in the large core diameter multimode fiber 212 with sufficient length can eventually become completely unpolarized light 13. Therefore, another configuration structure of the depolarization module 21 is, as shown in FIG. 4, the depolarization module 21 is a large core diameter multimode optical fiber 212 with a certain length, which is connected with the optical fiber splitter 221, and is arranged between the optical fiber splitter 221 and the optical fiber collimator 15. After the laser enters the optical fiber splitter 221, it is divided into multiple The light paths enter the corresponding large-core-diameter multimode fibers 212 respectively, and become completely unpolarized light 13 during the transmission process, which is subjected to depolarization first and then depolarization.

More specifically, as shown in FIG. 4 , the laser light enters the fiber splitter 221 through the fiber coupler 14 and is divided into multiple laser beams, and then each laser beam enters the corresponding large core diameter multimode fiber 212 respectively. It becomes completely unpolarized light 13 in the middle, and then output through the fiber collimator 15, and becomes polarized light through the polarizing module 23. The polarizing module 23 is a polarization beam splitter, and the completely unpolarized light 13 is divided into the polarization beam splitter by the polarization beam splitter. Horizontally polarized light and vertically polarized light, and the power of the two beams is the same. According to experiments, the large-core-diameter multimode optical fiber 212 may have a core diameter of 400 μm-800 μm and a length of the order of meters or more. The core diameter of the multimode fiber in the fiber splitter 221 is 50 microns or 62.5 microns, and the laser coupling efficiency from a multimode fiber with a thin core diameter to a multimode fiber with a thick core diameter is very high. The core diameter multimode fibers 212 are connected through an adapter flange, and the fiber collimator 15 is connected with the large core diameter multimode fibers 212 .

In addition, the way of laser beam splitting will also affect the optical power loss and splitting uniformity of the laser. One configuration structure of the beam splitting module 22 of the present invention includes a multi-level fiber splitter 221, and the laser or completely unpolarized light 13 passes through The optical fiber coupler 14 enters the optical fiber splitter 221 of the first stage, and the split light enters several optical fiber splitters 221 of the next stage until the required number of paths of light are obtained. Optical fiber splitter 221 is a commonly used optical splitting device in the field of communication equipment. It is used to divide one laser into n channels. n usually has specifications such as 2/4/8/16/32/64, and of course there are special values other than the above values. , From the type of fiber, the common ones are single-mode fiber splitter and multi-mode fiber splitter. The core diameter of single-mode fiber is relatively small (commonly below 10 microns), the coupling of the laser into the fiber is difficult, and the cost of the coupler is high; At the same time, the power transmitted by the single-mode fiber is much lower than that of the mode fiber, and the multi-mode fiber splitter is adopted in the present invention, which reduces the system cost. An optical fiber splitter 221 itself can be used as the optical splitting module 22. When the required number of laser beams is relatively large and a single optical fiber splitter 221 cannot meet the requirements, a multi-stage optical fiber splitter 221 can be used, and the next level The input interface of the optical fiber splitter 221 is connected to the output of the optical fiber splitter 221 of the upper stage, thereby increasing the number of output channels exponentially. However, the number of optical fiber splitters 221 is too many, which will cause optical power loss, uneven splitting and other adverse consequences. Many laser application systems, such as atomic magnetic sensors, require that the power deviation of each laser does not exceed 10%. Therefore, the actual In application, a one-stage or two-stage fiber splitter 221 is usually used. Those skilled in the art can understand that the number and specifications of the fiber splitters 221 are not limited in the embodiments of the present invention, and can be set according to the number of laser beams required in practical applications, for example, as shown in FIG. 5 In a specific example, the content and features of the light splitting method according to the embodiment of the present invention are described and disclosed by using a two-stage 2-way optical fiber splitter 221 to separate 8 paths of light. The splitting of 8 beams by the splitter 221 cannot be regarded as a limitation on the content and scope of the beam splitting method of the present preferred embodiment. Optionally, in other possible examples of the optical splitting method in this embodiment, the optical fiber splitter 221 used may also be, but not limited to, specifications such as 4/8/16/32/64, and may also be other than the above-mentioned values. However, due to the optimization of the fiber splitter 221 itself, the number of stages used can also be 3, 4, 5, etc., so that the power deviation of each channel can meet the requirements of the laser application system.

Since the number of optical fiber splitters is too many, it will cause adverse consequences such as loss of optical power and uneven splitting. Therefore, preferably, as shown in FIG. 6 , the optical splitting module 22 further includes an optical splitting device 222, which is provided with Before the multi-stage fiber splitter 221, the laser or completely unpolarized light 13 is preliminarily split by the optical splitting device 222, and the light after preliminary splitting enters the first-stage fiber splitter 221 through the fiber coupler 14, and then enters respectively Several optical fiber splitters 221 in the next stage until the required number of paths of light are obtained. The laser beam emitted by the laser 11 is divided into n paths by the optical beam splitting device 222. The optical beam splitting device 222 uses optical devices such as lenses, prisms, and mirrors to divide the laser input into multiple laser outputs. The emitted lasers are all free light in space, and the optical fiber coupler 14 is set after the optical splitting device 222, and the laser light split by the optical splitting device 222 is connected to the optical fiber splitter 221 of the next stage through the optical fiber coupler 14 for further processing. split light. In practical applications, for some laser emitting devices whose output interface is an optical fiber, the optical fiber collimator 15 needs to be used to export the laser light, and then the optical beam splitting device 222 is used for light splitting. The structure of the splitting device 222 is shown in FIG. 7 , but is not limited to the 8-channel splitting shown in FIG. 7 , which can be set according to the actual number of laser beams and the specifications and number of the subsequent fiber splitters 221 , which can be 2 , 4, 8, etc., can also be special numerical values other than the above-mentioned numerical values. The advantage of using the optical splitting device 222 is that the first-stage optical fiber splitter 221 can be reduced, so that the light splitting is more uniform and the loss is smaller.

The spectroscopic module 22 including the optical spectroscopic device 222 is combined with the above-mentioned depolarization module 21. When the depolarization module 21 selects the depolarizer 211, the depolarizer 211 and the optical spectroscopic device 222 are both optical devices, and there are two installation methods. One is to set the depolarizer 211 between the laser 11 and the optical beam splitting device 222. The laser first passes through the depolarizer 211 to become completely unpolarized light 13, and then enters the optical beam splitting device 222 for preliminary beam splitting. The unpolarized light 13 passes through the subsequent fiber coupler 14 and enters the next-level fiber splitter 221 for further splitting; the other is to set the depolarizer 211 between the optical splitting device 222 and the fiber coupler 14, and the laser passes through After the optical splitting device 222 performs preliminary splitting, each beam of light passes through the depolarizer 211 to become completely unpolarized light 13 , and then passes through the fiber coupler 14 into the next-stage fiber splitter 221 for further splitting.

As shown in FIG. 9 , it shows that a single atomic gas cell 51 according to a preferred embodiment of the present invention is injected into the multi-channel atomic gas cell 51 by the multiplex probe light 40 , and the probe light 40 is split by the polarization-maintaining transmission module. Or the pump light 30 is transmitted to the atomic magnetic sensing module 50, more specifically, the atomic gas chamber 51 therein. As mentioned above, a channel in the atomic gas chamber 51 refers to a path of detection light 40 passing through the atomic gas chamber 51 , the detection light 40 interacts with atoms to generate signals, and receives signals through the corresponding photoelectric sensing device 52 , and a path of detection light 40 corresponds to a channel.

The atomic gas chamber 51 contains gaseous atoms and buffer gas. The atoms move freely in space at high speed and continuously collide with the buffer gas molecules. The movement of the atomic group is restricted in a certain area, which is called the diffusion length. Under the action of a certain temperature and buffer gas pressure, the atomic diffusion length is a constant. The distance between adjacent probe lights 40 injected into the same atomic gas chamber 51 needs to be greater than the diffusion length, so as to ensure that different probe lights 40 detect different atoms. Therefore, it must be ensured that the distance between adjacent atoms in the same atomic gas cell 51 is greater than the diffusion length, so that the multiple detection lights 40 can share one atomic gas cell 51 to detect the magnetic field information of multiple points, which also saves space and cost.

As shown in FIG. 9 , four paths of detection light 40 are simultaneously injected into a single atomic gas cell 51 , and a corresponding number of four photoelectric sensing devices 52 are arranged on the side where the detection light 40 exits the atomic gas cell 51 for receiving the detection light 40 and the atomic gas cell 51 . Magnetic signals generated by the interaction. In this way, four paths of detection light 40 can simultaneously share a single atomic gas chamber 51 to measure information at four points, thereby improving the measurement efficiency.

It is worth mentioning that the number of probe lights 40 passing through a single atomic gas cell 51 is not limited in this preferred embodiment. For example, in the specific example shown in FIG. 9 , four probe lights 40 pass through A single atomic gas cell 51 is taken as an example to illustrate and disclose the content and features of the implementation method of the multi-channel atomic gas cell 51 in this preferred embodiment. It is considered to limit the content and scope of the implementation method of the multi-channel atomic gas chamber 51 of the present preferred embodiment. Optionally, in other possible examples of the implementation method of the multi-channel atomic gas cell 51 in the present preferred embodiment, the number of the detection light 40 passing through a single atomic gas cell 51 can also be implemented as, but not limited to, 1, 2 , 3, 5, 6, 7, 8, etc.

As shown in FIG. 10 , the atomic gas cells 51 are arranged in a row, at least one pump light 30 passes through all the atomic gas cells 51 on the same row, and each atomic gas cell 51 is injected by at least one probe light 40 . The photoelectric sensing device 52 corresponding to the number of the probe light 40 is arranged on the side of the exiting atomic gas chamber 51, a plurality of atomic gas chambers 51 are sequentially arranged on the same column, and at least one pump light 30 is sent from the atomic gas chambers 51 arranged at the head of the column. The gas cell 51 is injected, and the pump light 30 passes through all the atomic gas cells 51 on the same column, and is emitted from the atomic gas cell 51 arranged at the end of the column, so that multiple atomic gas cells 51 on the same column share the pump light. 30.

Preferably, a plurality of atomic gas cells 51 are arranged in sequence on the same straight line, the pump light 30 passes through all the atomic gas cells 51 on the same straight line, and at the same time, each atomic gas cell 51 on the same row is detected in multiple ways The light 40 is incident to form multiple channels for information measurement, thereby improving the efficiency of information measurement.

As shown in FIG. 10 , three atomic gas chambers 51 are arranged in the same row in sequence, and each atomic gas chamber 51 is passed through by two paths of detection light 40 . A number of 2 photoelectric sensing devices 52 are used to receive signals generated by the interaction of the probe light 40 with the atoms. In this way, it is realized that the two paths of detection light 40 share a single atomic gas cell 51 to measure information at two points at the same time, and further realize that a single row of three atomic gas cells 51 can simultaneously perform information measurement of six points.

Those skilled in the art can understand that the number of atomic gas chambers 51 arranged in sequence on the same column is not limited in this preferred embodiment, for example, in the specific example shown in FIG. The number of atomic gas chambers 51 on the same column is 3 as an example to illustrate and disclose the content and characteristics of the implementation method of the multi-channel atomic gas chamber 51 array of the present preferred embodiment, but the atoms arranged in the same column in sequence The number of the gas chambers 51 being three cannot be regarded as a limitation on the content and scope of the implementation method of the multi-channel atomic gas chamber 51 array of the present preferred embodiment. Optionally, in other possible examples of the implementation method of the multi-channel atomic gas chamber 51 array in this preferred embodiment, the number of atomic gas chambers 51 sequentially arranged on the same column can also be implemented as, but not limited to, 2. , 4, 5, 6, 7, 8, etc.

Those skilled in the art can also understand that the number of detection light 40 passing through a single atomic gas cell 51 is not limited in this preferred embodiment, for example, in the specific example shown in FIG. The light 40 passes through a single atomic gas cell 51 as an example to illustrate and disclose the content and features of the implementation method of the multi-channel atomic gas cell 51 array of the present preferred embodiment, but the quantity of the detection light 40 passing through the single atomic gas cell 51 is 2 channels cannot be regarded as a limitation on the content and scope of the implementation method of the multi-channel atomic gas cell 51 array of the present preferred embodiment. Optionally, in other possible examples of the implementation method of the multi-channel atomic gas cell 51 array in the present preferred embodiment, the number of the probe light 40 passing through a single atomic gas cell 51 can also be, but is not limited to, be implemented as 1, 3, 4, 5, 6, 7, 8, etc.

In addition, in order to improve the pumping efficiency, a plane mirror 57 is provided on the side where the pumping light 30 exits the atomic gas chamber 51 to reflect the pumping light 30 and return along the original path.

The pump light is circularly polarized light (left-handed circularly polarized or right-handed circularly polarized). For the reflector with dielectric film, the pump light will have a half-wave loss after passing through the plane reflector, which is equivalent to a phase deflection of 180 degrees. Since the reflected pump light is only changed from left-handed circularly polarized light to right-handed circularly polarized light for atoms (or from right-handed circularly polarized light to left-handed circularly polarized light), for atoms, the The pump light 30 reflected by the plane mirror 57 has the same function as the incident pump light 30 . By arranging a plane mirror 57 on the side where the pump light 30 exits the atomic gas chamber 51, secondary pumping is realized, and the pumping efficiency is improved.

As shown in FIG. 11 , the present invention further provides an array structure of atomic gas chambers 51 of a multi-channel atomic magnetic force sensing device, including multiple rows of atomic gas chambers 51 arranged in sequence, multiple paths of detection light 40 , and multiple paths of pump light. 30, and photoelectric sensing devices 52 corresponding to the number of detection lights 40. Each atomic gas cell 51 is injected by at least one probe light 40 , and the photoelectric sensing device 52 is arranged on the side of the probe light 40 exiting the atomic gas cell 51 to receive the signal generated by the interaction between the probe light 40 and the atoms, and the pump light 30 Pass through all atomic gas cells 51 on the same column.

Multiple rows of atomic gas cells 51 are arranged in sequence to form a lattice, and each row of atomic gas cells 51 is passed through at least one pump light 30 , so that all atomic gas cells 51 on the same row share the pump light 30 .

Preferably, all atomic gas chambers 51 on the same column are sequentially arranged on the same straight line. After the pump light 30 is collimated by the fiber collimator 15, it is converted into parallel light and passes through all the atomic gas cells 51 on the same straight line.

At the same time, each atomic gas cell 51 on the same column is injected by at least one probe light 40, and under the action of the pump light 30, a multi-channel gas cell is formed for information measurement, which improves the efficiency of information measurement.

As shown in FIG. 11 , 3 columns of atomic gas chambers 51 are arranged in sequence, each row consists of 3 atomic gas chambers 51 , each atomic gas chamber 51 is passed through by 2 paths of detection light 40 , and atoms are emitted from the detection light 40 Each side of the gas chamber 51 is provided with a corresponding number of two photoelectric sensing devices 52 for receiving the signals generated by the interaction between the probe light 40 and the atoms. In this way, the information measurement of six points at the same time by three atomic gas chambers 51 in a single row is realized, and the information measurement at eighteen points at the same time by three rows of nine atomic gas chambers 51 is further realized.

It is worth mentioning that the number of columns of the atomic gas chambers 51 arranged in sequence is not limited in this preferred embodiment, for example, in the specific example shown in FIG. The number of columns is 3 as an example to illustrate and disclose the content and features of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment, but the number of columns of the atomic gas chambers 51 arranged in sequence is 3 and cannot be regarded as a requirement for the present invention. Limitations of the content and scope of the multi-channel atomic gas cell 51 array system of the preferred embodiment. Optionally, in other possible examples of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment, the number of columns of the atomic gas chambers 51 arranged in sequence can also be implemented as, but not limited to, 1, 2, 4, 5, 6, 7, 8, etc.

Those skilled in the art can understand that the number of atomic gas chambers 51 arranged in sequence on the same column is not limited in this preferred embodiment, for example, in the specific example shown in FIG. The number of atomic gas chambers 51 on the same row is 3 as an example to illustrate and disclose the content and features of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment, but the atomic gas chambers are arranged in sequence on the same row The number of 51 being three should not be considered as a limitation on the content and scope of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment. Optionally, in other possible examples of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment, the number of atomic gas chambers 51 sequentially arranged on the same column can also be implemented as, but not limited to, 1, 2 , 4, 5, 6, 7, 8, etc.

Those skilled in the art can also understand that the number of detection light 40 passing through a single atomic gas cell 51 is not limited in this preferred embodiment, for example, in the specific example shown in FIG. The light 40 passes through a single atomic gas cell 51 as an example to illustrate and disclose the content and features of the multi-channel atomic gas cell 51 array system of the preferred embodiment, but the number of detection lights 40 passing through a single atomic gas cell 51 is 2 and It should not be considered as limiting the content and scope of the multi-channel atomic gas cell 51 array system of the present preferred embodiment. Optionally, in other possible examples of the multi-channel atomic gas chamber 51 array system of the present preferred embodiment, the number of the detection light 40 passing through a single atomic gas chamber 51 can also be implemented as, but not limited to, 1, 3, 4, 5, 6, 7, 8, etc.

Since the surface of the atomic gas chamber 51 has certain reflections, in order to avoid interference of the probe light 40 reflected to other positions of the system, preferably, the probe light 40 is perpendicular to the surface of the atomic gas chamber 51 and passes through the atomic gas chamber 51 .

Preferably, the pump light 30 passes through all the atomic gas cells 51 on the same column perpendicular to the probe light 40 .

It is worth mentioning that the multi-channel atomic gas chamber 51 array system further includes at least one plane mirror 57, and the plane mirror 57 is arranged on the side of the pump light 30 exiting the atomic gas chamber 51 for reflecting the pump light 30 along the Return the same way to improve the pumping efficiency.

Due to the increase in the number of atomic gas chambers 51 arranged, a single pump light 30 cannot meet the requirements of a multi-channel atomic magnetic sensing device. Therefore, the pump light 30 can also use the polarization obtained by splitting through another polarization-maintaining transmission system 20 The light then forms parallel circularly polarized light through the half-wave plate 31 and the quarter-wave plate 32, and enters the atomic gas chamber 51 as the pump light 30 to excite the alkali metal atoms. The configuration structure is the same as the above-mentioned spectroscopic polarization-maintaining transmission system 20 .

The above-mentioned embodiments are only preferred embodiments of the present invention, and cannot be used to limit the scope of protection of the present invention. Any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of the present invention. Scope of protection claimed.

Claims (10)

1. A multichannel pulse pumping atomic magnetic force sensing device is characterized by comprising

At least one split polarization maintaining transmission system;

At least one path of pump light;

The multi-path detection light comprises polarized light obtained by light splitting through the light splitting polarization-preserving transmission system;

The atomic magnetic force sensing module is connected with the light splitting polarization-maintaining transmission system and receives the detection light;

The atomic magnetic force sensing module comprises at least one row of atomic air chambers which are sequentially arranged, and photoelectric sensing devices corresponding to the quantity of the detection light, wherein each atomic air chamber is penetrated by at least one path of the detection light, the distance between the detection light penetrating through the same atomic air chamber is larger than the diffusion length of atoms under certain buffer gas pressure at a certain temperature, the photoelectric sensing devices are arranged on one side of the atomic air chamber, which is emitted by the detection light, and are used for receiving signals generated by the interaction between the detection light and the atoms, and the pumping light penetrates through all the atomic air chambers on the same row;

The light-splitting polarization-maintaining transmission system comprises a polarization-removing module, a light-splitting module and a polarization-generating module, wherein the polarization-removing module is used for changing laser into completely unpolarized light, the polarization-generating module is used for converting the laser which is changed into the completely unpolarized light into polarized light, and the polarization-removing module is connected with the light-splitting module and is arranged in front of the polarization-generating module.

2. The multi-channel pulse pumping atomic magnetic force sensing device as claimed in claim 1, wherein the optical splitting module comprises a fiber splitter, a fiber coupler is connected to the front of the fiber splitter, and a fiber collimator is arranged behind the fiber coupler, and the fiber collimator is arranged in front of the polarization module.

3. The multi-channel pulsed pump atomic magnetic force sensing device of claim 2, wherein the depolarization module is a depolarizer disposed before the fiber splitter or after the fiber collimator.

4. The multi-channel pulse pumping atomic magnetic force sensing device as claimed in claim 2, wherein the depolarization module is a large-core multimode fiber having a certain length, is connected to the fiber splitter, and is disposed between the fiber splitter and the fiber collimator.

5. The apparatus according to claim 2, 3 or 4, wherein the optical splitting module comprises a plurality of stages of the fiber splitters, and the fiber coupler is connected to a first stage of the fiber splitters.

6. the multi-channel pulsed pumping atomic magnetic force sensing device according to claim 5, wherein the optical splitting module comprises an optical splitting device, and the fiber coupler is disposed between the optical splitting device and a multi-stage fiber splitter.

7. The multi-channel pulsed pumping atomic magnetic force sensing device according to any one of claims 1 to 4, wherein the atomic gas chambers are arranged in sequence on the same straight line.

8. The multi-channel pulsed atomic pumping magnetic force sensing device according to any one of claims 1 to 4, wherein the probe light is perpendicular to the surface of the atomic gas cell and the pump light at the same time.

9. The multi-channel pulsed atomic pumping magnetic force sensing device according to any one of claims 1 to 4, further comprising at least one plane mirror disposed at a side where the pump light exits the atomic gas cell for reflecting the pump light back along the original path.

10. The multi-channel pulsed pump atomic magnetic force sensing device of any one of claims 1 to 4, wherein the pump light comprises polarized light split by another of the split polarization-preserving transmission systems.