CN201307089Y - A Terahertz wave detector and a detection system - Google Patents

Abstract

The utility model is applicable to the technical field of terahertz wave detection, and provides a terahertz wave detector and a detection system. The terahertz wave detector includes: receiving a first optical signal, performing filtering, focusing and outputting a second optical signal lens; a detection element that converts the second optical signal output by the lens into an electrical signal output; a signal amplification circuit that amplifies and outputs the electrical signal output by the detection element after filtering; and provides the detection element and the signal The amplifying circuit provides the power supply of the working voltage. The terahertz wave detector and detection system provided by the utility model can detect the terahertz wave, thereby benefiting the development of all other terahertz wave scientific and technological researches.

Description

A terahertz wave detector and detection system

technical field

The utility model belongs to the technical field of terahertz wave detection, in particular to a terahertz wave detector and a detection system.

Background technique

Terahertz (Terahertz, THz, 1THz=10 ¹² Hz) waves refer to electromagnetic waves with a frequency in the range of 0.1THz to 10THz (that is, a wavelength of 3mm to 30μm). category. THz wave has good penetrability to many dielectric materials and non-polar liquids, and can detect opaque objects through perspective; its photon energy is very low, which is safe for living organisms; THz wave contains rich spectral information and has Good spectral resolution characteristics. Therefore, THz technology has unique advantages in fields such as biomedicine and safety monitoring.

Terahertz wave radiation source and terahertz wave detection technology affect the development of all other terahertz wave science and technology research. However, the prior art does not disclose detection techniques for terahertz waves.

Utility model content

The purpose of the embodiments of the present invention is to provide a terahertz wave detector capable of detecting terahertz waves.

The embodiment of the utility model is achieved in this way, a terahertz wave detector, the terahertz wave detector includes:

A lens that receives the first optical signal, performs filtering, and focuses to output the second optical signal;

a detection element that converts the second optical signal output by the lens into an electrical signal;

A signal amplification circuit that amplifies and outputs the electrical signal output by the detection element after filtering; and

A power supply of working voltage is provided for the detecting element and the signal amplifying circuit.

In the embodiment of the present invention, the terahertz wave detector further includes: a mechanical device for carrying and fixing the detection element, the lens, the signal amplification circuit and the power supply.

Wherein, the detection element is an infrared pyroelectric sensor.

Wherein, the lens is a Fresnel lens.

In an embodiment of the utility model, the signal amplification circuit includes:

DC voltage converters that convert DC positive voltages to DC negative voltages;

a filter circuit for filtering the electrical signal output by the detection element; and

An operational amplifier whose negative voltage input terminal is connected to the output terminal of the DC voltage converter to receive the DC negative voltage; its positive voltage input terminal is connected to the first node to receive the DC positive voltage output by the power supply; its signal input terminal Connected to the output end of the filter circuit, the filtered electrical signal is positively amplified and then output.

Another object of the embodiment of the present invention is to provide a terahertz wave detection system, including: a terahertz wave radiation source that radiates optical signals; a parabolic mirror that collects the optical signals and incidents them on the sample; When the signal is incident on the sample, a chopper that modulates the optical signal; a terahertz wave detector that receives the modulated optical signal loaded with sample information, processes it and outputs it; and converts the terahertz wave detector The output of the oscilloscope is displayed; the terahertz wave detector further includes:

A lens that receives the first optical signal, performs filtering, and focuses to output the second optical signal;

a detection element that converts the second optical signal output by the lens into an electrical signal;

A signal amplification circuit that amplifies and outputs the electrical signal output by the detection element after filtering; and

A power supply of working voltage is provided for the detecting element and the signal amplifying circuit.

In the embodiment of the present invention, the terahertz wave detector further includes: a mechanical device for carrying and fixing the detection element, the lens, the signal amplification circuit and the power supply.

Wherein, the detection element is an infrared pyroelectric sensor.

Wherein, the lens is a Fresnel lens.

The terahertz wave detector and the detection system provided by the embodiment of the utility model can detect the terahertz wave, thereby benefiting the development of all other terahertz wave scientific and technological researches.

Description of drawings

Fig. 1 is a schematic structural diagram of a terahertz wave detection system provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a terahertz wave detector provided by an embodiment of the present invention;

Fig. 3 is a circuit diagram of the signal amplifying circuit provided by the embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

The embodiment of the utility model adopts the terahertz wave detector to detect the terahertz wave well.

The terahertz wave detector provided by the embodiment of the utility model is mainly used in the terahertz wave detection system. Fig. 1 shows the structure of the terahertz wave detection system. part, as detailed below.

The terahertz wave detection system includes: a terahertz wave radiation source 6, which radiates an optical signal; a parabolic mirror 7, which collects the optical signal radiated by the terahertz wave radiation source 6, and incident it on the sample 9; When it reaches the sample, the optical signal is modulated; the terahertz wave detector 10 receives the modulated optical signal loaded with sample information, and outputs it after processing; and the oscilloscope 11 displays the output of the terahertz wave detector 10 .

Wherein, the structure of the terahertz wave detector 10 is shown in FIG. 2 . For the convenience of description, only the parts related to the embodiment of the present utility model are shown, and the details are as follows.

The terahertz wave detector 10 includes: a lens 101, which is used to receive the first optical signal, perform filtering and then focus and output the second optical signal; a detection element 102, which converts the second optical signal output by the lens 101 into an electrical signal for output; signal amplification The circuit 103 filters and amplifies the electrical signal output by the detection element 102 ; the power supply 104 is used to provide the detection element 102 and the signal amplification circuit 103 with working voltage. As an embodiment of the present invention, the terahertz wave detector 10 also includes a mechanical device (not shown in the figure), which is used to carry and fix the detection element 102, the lens 101, the signal amplification circuit 103 and the power supply 104 to reduce environmental interference .

As an embodiment of the present invention, the detection element 102 is an infrared pyroelectric sensor. The infrared pyroelectric sensor can be LHI778, LHI968, RE200B, etc. Among them, LHI778 has the best response characteristic, the sensitivity can reach 4000V/W, and the NEP can reach 7.5×10 ^-10 WHz ^-2 . The lens 101 is a Fresnel lens, and the Fresnel lens can be Fresnel8120, Fresnel7709, etc., wherein the embodiment of the utility model adopts Fresnel8120, and its size is just enough to be directly placed on the LHI778 infrared pyroelectric sensor. As another embodiment of the present invention, the power supply 104 can be a 3-12V DC power supply, and this embodiment of the present invention uses a +9V laminated battery.

In the embodiment of the utility model, the structure of the mechanical device is a sealed cube, and the front end and top of the cube are detachable; there are small holes on the front panel of the cube, which are used to fix the lens 101 and guide light waves; the front end of the cube also has grooves , used to place the signal amplifying circuit 103 and the detection element 102; the upper end of the cube also has a groove for placing a +9V laminated battery, and there are two small grooves in the middle for the wire connection of the signal amplifying circuit 103, the laminated battery and the switch SW , and the wire connection between the signal amplifying circuit 103 and the output BNC socket J2. The switch SW and the output socket J2 are fixed on the rear panel. The mechanism is made of aluminum.

As an embodiment of the present invention, the detecting element 102 and the signal amplifying circuit 103 can be connected by welding; they can also be connected directly by wires.

In the embodiment of the present invention, the signal amplifying circuit 103 is a millivolt-level to volt-level voltage amplifying circuit, and its specific circuit is shown in FIG. Details are as follows.

The signal amplifying circuit 103 includes: a DC voltage converter 31, which converts a positive DC voltage into a negative DC voltage; a filter circuit 32, which filters the electrical signal output by the detection element J1 (i.e. the detection element 102 in Figure 2); and an operational amplifier 33, its negative voltage input terminal is connected to the output terminal of the DC voltage converter 31 to receive the DC negative voltage; its positive voltage input terminal is connected to the first node S0 to receive the DC positive voltage output by the power supply 104; its signal input terminal is connected to The output end of the filter circuit 32 is to forward-amplify the filtered electrical signal and output it.

The DC voltage converter 31 can be an ICL7660 series chip, including 7660, 7660S, 7662, etc., and the embodiment of the utility model adopts 7660S, which can convert the positive voltage between +1.5V to +10V into a negative voltage for the operational amplifier 33 used. As an embodiment of the present invention, the DC voltage converter 31 includes 8 pins, PIN1 is a boost pin, PIN2 is the positive pole of an external charge pump capacitor C5, PIN3 is an input low potential and ground terminal, and PIN4 is an external charge The negative pole of the pump capacitor C5, PIN5 is the output pin, which can be connected to the negative pole of the output capacitor, PIN6 is the low voltage selection terminal, PIN7 is the external clock or external capacitor terminal, PIN8 is the power supply terminal, input high potential.

The detection element J1 includes 3 pins, PIN1 is the G terminal, which is grounded; PIN2 is the S terminal, which is the signal output terminal; PIN3 is the D terminal, which is connected to the first node S0. As an embodiment of the present invention, the detection element J1 is welded on the signal amplifying circuit 103 .

As an embodiment of the present utility model, the filter circuit 32 further includes: a filter capacitor C4 and a filter resistor R3; one end of the filter capacitor C4 is connected to the output terminal PIN2 of the detection element J1, and the other end is connected to the signal input terminal IN+ of the operational amplifier 33 , also grounded through the filter resistor R3. The filter resistor R3 and the filter capacitor C4 are used to filter low-frequency noise in the electrical signal output by the detection element J1.

The operational amplifier 33 can be OP07 series chips and uA741, uA709, LM301, LM308, LF356, OP37, max427 and other chips, and the embodiment of the utility model adopts OP07AH, which has very low input offset voltage and drift, and is especially suitable for amplifying weak signals. As an embodiment of the present invention, the operational amplifier 33 includes 8 pins, and PIN1 and PIN8 are zero-adjusting terminals, which are used for indirect adjustable resistors on pins 1 and 8, and the middle tap of the adjustable resistor is connected to the power supply pin, and PIN2 It is the inverting input terminal, PIN3 is the non-inverting input terminal and ground terminal, PIN4 is the negative power supply terminal, PIN5 is the empty leg tube, PIN6 is the output terminal, PIN7 is the positive power supply terminal, and PIN8 is the zero adjustment terminal.

The BNC socket J2 includes 2 pins, PIN1 is grounded; PIN2 is connected to PIN6 of the operational amplifier 33; the BNC socket J2 is fixed on the mechanical shell, and is connected with the signal amplifying circuit 103 through wires. The coaxial cable with BNC standard plugs at both ends is connected to the oscilloscope through the BNC standard socket J2.

In the embodiment of the present utility model, the signal amplifying circuit 103 further includes: resistors R1, R2, R4, R5 and capacitors C1, C2, C3, C5, wherein the capacitor C5 is connected to the PIN2 and PIN4 of the DC voltage converter 31 In between, the capacitor C5 is an external charge pump capacitor, also called an energy storage capacitor, and assists the internal structure of the DC voltage converter 31 to realize the transformation from positive voltage to negative voltage. One end of the resistor R5 is connected to the power supply 104 through the switch SW, the other end is connected to the power supply terminal PIN8 of the DC voltage converter 31 as the first node S0, and the other end is also grounded through the capacitor C2; the resistor R5 acts as a current limiting and voltage limiting function, The capacitor C2 is used to reduce the fluctuation of the DC power supply and smooth the waveform of the power supply. The PIN5 of the DC voltage converter 31 is connected to the PIN4 of the operational amplifier 33, and grounded through the capacitor C3; the capacitor C3 is used to reduce the negative polarity DC power fluctuation generated by the DC voltage converter 31 and smooth the negative polarity DC power waveform. The PIN3 of the DC voltage converter 31 is grounded, while the PIN1, PIN6, and PIN7 are not connected in the air. One end of the resistor R4 is connected to the output end of the detection element J1, and the other end is connected to the PIN4 of the operational amplifier 33, and the resistor R4 acts as a clamp. The PIN7 of the operational amplifier 33 is connected to the first node S0; the PIN2 of the operational amplifier 33 is grounded through the resistor R1; the PIN6 of the operational amplifier 33 is grounded through the resistors R2 and R1 in turn, and the capacitor C1 is connected in parallel with the resistor R2; the capacitor C1 functions to filter out the amplified signal For the role of medium and high frequency components, the amplification factor of the electrical signal can be determined by the resistance values of resistors R1 and R2, and the multiple is about R2/R1. The PIN3 of the operational amplifier 33 is connected to the output of the filter circuit 32, while the PIN1, PIN5 and PIN8 are not connected in the air.

The working principle of the terahertz wave detection system provided by the embodiment of the utility model is described as follows: the terahertz wave emitted from the terahertz source 6 is collected by the parabolic mirror 7 and incident on the sample 9 on the sample stage, and at the same time the light is chopped 8 (SR504, 4-40Hz) modulation, the terahertz light transmitted or reflected from the sample 9 loads the information of the sample, this signal light is collected and incident on the lens 101, the lens 101 filters out the interference light such as visible light in the environment , and focus the signal light onto the detection element 102, the detection element 102 converts the light signal into an electrical signal, and inputs it to the signal amplifying circuit 103, and the signal amplifying circuit 103 first realizes the transformation from the positive power supply (+9V) to the negative power supply to obtain The positive and negative power supply (±9V) required for the operation of the operational amplifier then filters and amplifies the electrical signal, and displays the detection result on the oscilloscope 11 .

The terahertz wave detector provided by the embodiment of the utility model can detect the weak signal terahertz wave. Similarly, in the case of adding other devices and software, the terahertz wave detector provided by the embodiment of the utility model is also suitable for Scanning imaging and non-destructive detection of metal objects (such as knives, etc.) hidden in newspapers and other packages.

The terahertz wave detector and detection system provided by the embodiment of the utility model can detect the terahertz wave, which is beneficial to the development of all other terahertz wave science and technology research; at the same time, the terahertz wave detection provided by the embodiment of the utility model The infrared pyroelectric sensor is used in the device, which makes the terahertz wave detection fast in response, high in sensitivity and low in cost.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (9)

1. A terahertz wave detector, characterized in that the terahertz wave detector comprises: A lens that receives the first optical signal, performs filtering, and focuses to output the second optical signal; a detection element that converts the second optical signal output by the lens into an electrical signal; A signal amplification circuit that amplifies and outputs the electrical signal output by the detection element after filtering; and A power supply of working voltage is provided for the detecting element and the signal amplifying circuit. 2. The terahertz wave detector according to claim 1, characterized in that, the terahertz wave detector further comprises: carrying and fixing the detection element, the lens, the signal amplification circuit and the power supply mechanical device. 3. The terahertz wave detector according to claim 1, wherein the detection element is an infrared pyroelectric sensor. 4. The terahertz wave detector according to claim 1, wherein the lens is a Fresnel lens. 5. The terahertz wave detector according to claim 1, wherein the signal amplification circuit comprises: DC voltage converters that convert DC positive voltages to DC negative voltages; a filter circuit for filtering the electrical signal output by the detection element; and An operational amplifier whose negative voltage input terminal is connected to the output terminal of the DC voltage converter to receive the DC negative voltage; its positive voltage input terminal is connected to the first node to receive the DC positive voltage output by the power supply; its signal input terminal Connected to the output end of the filter circuit, the filtered electrical signal is positively amplified and then output. 6. A terahertz wave detection system, comprising: a terahertz wave radiation source that radiates an optical signal; a parabolic mirror that collects the optical signal and is incident on a sample; when the optical signal is incident on the sample, modulates the An optical chopper for the optical signal; a terahertz wave detector that receives the modulated optical signal loaded with sample information and outputs it after processing; and an oscilloscope that displays the output of the terahertz wave detector; its features In that, the terahertz wave detector further includes: A lens that receives the first optical signal, performs filtering, and focuses to output the second optical signal; a detection element that converts the second optical signal output by the lens into an electrical signal; A signal amplification circuit that amplifies and outputs the electrical signal output by the detection element after filtering; and A power supply of working voltage is provided for the detecting element and the signal amplifying circuit. 7. The terahertz wave detection system according to claim 6, wherein the terahertz wave detector further comprises: carrying and fixing the detection element, the lens, the signal amplification circuit and the power supply mechanical device. 8. The terahertz wave detection system according to claim 6, wherein the detection element is an infrared pyroelectric sensor. 9. The terahertz wave detection system according to claim 6, wherein the lens is a Fresnel lens.

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