LT6046B - Change-over device for adjustable optical mounts and a system comprising such devices - Google Patents

Abstract

A change-over opto-mechanical device, which comprises a movable part having plurality of adjustable optical mounts (2) attached thereto. Optical element tilt can be precisely adjusted in at least two spatial directions. The said device can be easily rotated or linearly translated in order to bring the pre-adjusted optical elements in the optical path of a laser beam, thus enabling rapid switching between different optical components, without the need of constant fine realignment. The invention is especially suitable for use in multiple wavelength radiation laser systems using the same optical path or beam line. The movable part can be formed of a turret-like rotating device (1, 12) or a linear translation stage (15).

Description

FIELD OF INVENTION

The present invention relates to optomechanical devices or devices having movable sensible optical elements for controlling optical parameters such as reflectance, transmittance, intensity or energy density per unit area, color or spectrum, phase, polarization or direction of light propagation. More particularly, the present invention relates to the versatile control of laser source radiation using readily replaceable and adjustable optical elements of any type.

TECHNICAL LEVEL

Laser light sources are commonly used in research and industrial applications. Several optical devices or elements (eg lenses, mirrors, polarizers) must be used and interchanged to achieve accurate control of the laser beam parameters. Typically, such devices and elements are placed in the optical path and accurately positioned by the incident beam of the incident laser beam, otherwise inaccurate positioning may adversely affect the optical tuning, process repeatability, or damage.

Due to the high precision requirements, the optical tuning process usually takes time. Therefore, periodic reconfiguration of the optical path by changing or re-adjusting its components reduces the operating time of the laser system.

Special holders are needed for positioning and positioning optical elements in space. Not all holders are easy to replace and adjust in optical circuits, further complicating the optical circuit alignment process.

Holders that accommodate multiple optical elements and are adapted for rapid replacement are used to simplify reconfiguration of the optical system.

PCT Patent Application No. JP 11194259 published July 21, 1999 describes a method for tilting an independent optical element at an independent angle. There is provided a tilting mechanism for tilting an optical element, wherein the element is selected and positioned on the optical axis and aligned with respect to this axis. Many filters, such as optical elements, are arranged on the spinner essentially in a circle, where the center of the circle coincides with the axis of the spinner. The filter, selected and placed in the optical axis alongside the other filters, is positioned so that it can be tilted relative to the optical axis by a tilting mechanism. Specifically, the filter is held by the housing. A pair of protruding support axles is provided for the frame. The support axes hold the filter so that it can rotate easily. The supporting axes are oriented tangentially to a circle whose center coincides with the axis of rotation of the spinner, and the filter rotates with the support axes, moving in the same tangential direction as the center. Thus, it can be tilted relative to the optical axis. A rotating mechanism rotating the filter to a predetermined angle, with its support axes corresponding to the center, is provided as a tilting mechanism.

U.S. Pat. US5684624, published 4/11/1997, discloses a swapping device having a plurality of centered receiving rings embedded in a sliding bearing for optical components. The spring element having a plurality of tongues extending in the longitudinal direction is rolled so that in each case the successive sides of the adjacent tongues rest on the edge of the receiving ring by pressing against the springs.

Previous inventions disclose solutions where rotating spinners are used as swap devices for specific optical elements to increase flexibility and functionality of a given optical system. However, the solutions described are limited to one type and size of optical element. In addition, optical planes of optical elements are not precisely tuned and with sufficient travel to meet the requirements of reconfigurable optical paths, such as multiple wavelength radiation from one or more sources, as well as imaging systems. Also, they are designed so that they can only be positioned on specific devices such as microscopes. This severely limits applications, for example, they cannot be applied to a reconfigurable optical path for complex laser systems with multiple wavelength radiation sources.

THE SUBSTANCE OF THE INVENTION

To overcome the above disadvantages, the present invention provides a universal swapping device capable of storing, accurately justifying, and delivering one or more optical elements or combinations thereof to an optical path using one or more laser beams of different wavelengths or polarizations, or radiation from other light sources. Said optical elements are mounted in optical holders having at least two degrees of freedom, i.e. are tuned and tuned in at least two directions, depending on the radiation parameters of several sources, such as beam propagation direction, spectrum, fiber structure and shape, and many others. Subsequently, the optical path can be modified more rapidly to the desired wavelength or other radiation parameters by exchanging pre-sensed elements with one another, using rotation or linear displacement. This method and device reduce the time required to reconfigure the optical system.

In a preferred embodiment, the device comprises a rotor (1) and a plurality of adjustable optical holders (2) for holding individual optical elements. The rotor part (1) has a plurality of sockets for attaching to the holders (2). The tilt of each bracket is precisely controlled in at least two spatial directions by two fine-tuning screws (4) or micro-actuators disposed on the rotor (1).

The rotor (1) is mounted on an axle (9) which allows rotation in two directions such that the optical elements can be replaced either through indexed positions having a position locking element (stop means) or by independent control by manual or motorized means. The axle may be mounted on a support base (10). Rotation of the rotor is done by hand or by attaching the rotor axis to the motor or other type of gear.

Several such switching devices can be combined in various configurations to form more sophisticated optical devices such as fiber attenuators, dividers, deflection systems, and others.

In another embodiment, during the optical element exchange, the linear shift action is used to insert the optical element into the optical axis. This is achieved by utilizing a straight-forward table (15) with a platform (16) for mounting one or more manually or machine-controlled holders (2). The optical holders (2) require a support (17) which is mounted directly on the platform (16). An additional motor (18) can be fitted to the tilt table.

Both the rotor (1) and the linear displacement platform (16) have locking means adapted to lock said moving parts (1, 12, 16) in stable and reproducible positions. However, the same principle can be applied in a configuration that does not use locking in marked positions.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

In order to better understand the invention and evaluate its practical applications, the following illustrative drawings are provided. The drawings are given by way of example only and in no way limit the scope of the invention.

Fig. 1 is an isometric view of a rotary swap device.

Fig. 2 is a side view of a rotary swap device.

Figure 3 is an isometric front view of a dual disc rotor system.

Figure 4 is an isometric end view of a dual disc rotor system.

Figure 5 is a front view of a dual disc rotor system.

Fig. 6 is a rear view of a dual disc rotor system.

Fig. 7 shows a rotary table type swap device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is a universal swapping device capable of introducing one or more optical elements into an optical path used for one or more laser beams of different wavelengths. Fluctuating optical elements can compensate for misalignment of fibers traveling in different directions by returning them to the same optical path. The device consists of a moving part such as a rotor (1) or a linear displacement platform (16) and separate independently adjustable holders (2) for holding separate optical elements such as mirrors, polarizers. This device is also suitable for filters in permeability mode, whose positioning does not always require accurate positioning, but surface reflections should be avoided. The rotor (1) has more than one location for holding said holders (2). The tilt of each bracket is precisely controlled in two spatial directions by two precision-adjusting screws (4) located on the rotor (1) or intermediate support members (17). The bracket (2) is adapted to rest on three support points (5, 6), two of which are the ends (5) of the said precision screws (4), the third, in a preferred embodiment, being a stationary screw (6). The rotor (1) must be mounted on an axle (9) which can additionally be mounted on an adjustable link (not shown in the drawings). The rotor (1) is driven manually or by a stepper motor. Correspondingly, in the case of a linear displacement platform (16), the displacement is performed manually or by a stepper motor. In the embodiment without stepper motor (18), both, the rotor (1) and the linear displacement platform (16) preferably have locking means adapted to lock said moving parts (1, 16) in stable and reproducible positions. In the case of a built-in stepper motor (18), feedback systems are provided to ensure reproducible positioning in the intended positions.

In another embodiment, the optical holders (2) are held close to the rotor (1, 12) by springs (7) or magnets (not shown in the drawings). In the case of magnets, the tips of the precision justification and stationary screws (6) may be magnetic. In the case of springs (7), both ends of the spring are mounted together with support elements (14) which rest on the edges of the rotor (1, 12).

In another embodiment, the entire rotor assembly is secured to an adjustable height post (10), which is secured to a base plate (11).

In another embodiment, the adjustable brackets (2) are based on microprocessors such as piezo elements, micro-step motors, pneumatic or hydraulic elements or the like. This method of attachment allows remote angular adjustment of said brackets (2).

In another embodiment, the swapping device comprises a plurality of rotor-type rotors (1, 12), thereby forming a system wherein a plurality of optical elements are arranged in the optical path, one behind the other. An example of such an embodiment could be a laser beam power attenuator. Such a device is mounted with interconnected discs of holders (1, 12), wherein the optical holders (2) are used to hold thin film, Bruster type, dual prism or other types of polarizers. The second rotor retainer disc (12) has a central notch (19) for passing the laser beam to access optical elements mounted on the first rotor (1). The second disk (12) is rigidly connected to the first disk (1) by a plurality of cylindrical supports (13) or fixed to a common central axis (9). One or more polarizers and / or the phase plate are mounted in optical holders (2) in configurations corresponding to different wavelengths and power suppression levels so that the incident laser beam is suppressed and directed in the desired direction. The exact placement and justification of polarizers is a time consuming task and therefore the present invention avoids routine re-sensing work and significantly reduces such system-occupied space as compared to systems having individual attenuators for different wavelengths of radiation.

In another embodiment, the damper has two adjustable matched reflective polarizers positioned at each position and a phase plate. Pairs of polarizers and phase plates form sets of optical components for high-contrast attenuation. Each set is designed for a specific wavelength and operates by spatially separating different light polarizations at the output, requiring an accurate angular arrangement with respect to incident light. Applications such as laser processing of materials, optical damage threshold studies, excitation-probe spectroscopy require the use of different wavelengths in the same optical path to compensate for misalignment of different fibers, and therefore the present invention would be useful.

In another embodiment, the displacement mechanism is replaced by a linear displacement table (15). The linear displacement table (15) consists of a movable platform (16) with optical brackets (2) attached through a support member (17). A stepper motor (18) may be provided for automating said exchange device. This embodiment can be used in both the above and the following applications.

In another embodiment, the linear-shift table-type swapping device is completed with at least one additional linear or rotary-tilt table (not shown in the drawings). The aforementioned second shift table allows for the exchange of another set of optical components, which can result in complex systems. It should be apparent to one skilled in the art that any combination of swap devices capable of holding a controlled optical carrier may be integrated into optical paths of complex configurations.

In another embodiment, said rotary swap device is adapted to hold a plurality of nonlinear crystals which are used to vary the incident laser wavelength. The crystals are mounted in optical holders (2) and are fitted with two precision justification screws (4) to align the axes of said nonlinear crystals with one or more fibers or otherwise achieve phase synchronization conditions. The precise nonlinear crystal alignment angle is particularly important for wave mixing and parametric amplification processes.

In another embodiment, the swapping device is adapted to accommodate multiple mirrors for directing light of different wavelengths into a single working area, or to direct light coming from one optical path to different working areas. This allows one optical path to be used, saving space and increasing system uptime.

In another embodiment, one or more of the swapping devices is provided with a system consisting of lenses and / or apertures and / or waveguides and / or phase wafers and / or axons for light spatial filtration, beamforming, or the like. This is important for modern research applications that require different and complex types of fiber profiles. Examples of applications include the generation of optical vortexes used as optical tweezers, Bessel fibers, Airy fibers, multi-focal fibers, and many others.

The shape of the adjustable holders (2) corresponds to the size and shape of the optical component.

The number of brackets (2) is not limited as long as they can all be accommodated on the moving part, i.e. rotor (1, 12) or platform (16).

There are many applications which require precision positioning and frequent replacement of optical elements, and the present invention can be used alone or in combination with other optical devices.

Claims (13)

DEFINITION OF INVENTION A swapping device for swapping optical components, characterized in that said swapping device has two or more adjustable optical component holders mounted on at least one movable part (1, 12, 16), said optical holders can be sensed in at least two directions. A replacement device according to claim 1, characterized in that said at least one movable part acts as a rotating member (1, 12). A replacement device according to claim 1, characterized in that said at least one moving part acts as a linear displacement member (16). Swap device according to one of Claims 1 to 2, characterized in that said at least one rotating member (1, 12) is a rotary device having a rotor (1, 12) and an axle (9). 5. A switching device according to claim 4, characterized in that the rotor (1, 12) is adapted to be driven by an electric motor. A replacement device according to claim 4, characterized in that the rotor (1, 12) is adapted to be rotated by hand and has locking means for stopping the rotor in predetermined positions. Swap device according to one of Claims 1 to 6, characterized in that the adjustable brackets (2) are supported on the moving part (1, 12) or the adapter (17) attached to it, at least on three supporting parts. Replacement device according to one of Claims 1 to 7, characterized in that said support members have at least two precision-adjusting screws (4) and / or a stationary screw (6). A replacement device according to any one of claims 1 to 7, characterized in that said support members have at least two micro-actuators. Swap device according to claim 3, characterized in that the linear shift element is a platform (16) mounted on a linear shift table (15). A replacement device according to one of claims 1, 3 or 10, characterized in that said linear displacement table (15) is a motorized displacement table. 12. A system having a single optical path for delivering a plurality of wavelengths of radiation to a working region, characterized in that said path is provided with one or more switching devices according to one of claims 1 to 11. 13. The system of claim 12, wherein said system is adapted to operate as an optical power attenuator or part thereof, or as a laser material processing system, or a beamforming system, or a spectroscopic system, or as part of a light-induced optical damage threshold testing system, either a fiber deflection system or a fiber deflection system.