Automatic testing system for phase matching angle and matching temperature of KTP crystal

Abstract

The utility model provides a KTP crystal phase matching angle and matching temperature automatic test system. Laser emitting unit emits the laser of 1064nm wavelength; Crystal seat includes rotating device and temperature control device, is provided with temperature sensor on crystal seat; KTP crystal sets up on crystal seat, and KTP crystal sets up in the back of crystal seat, and KTP crystal is located on the propagation light path of light; Power detector sets up in the back of KTP crystal, sets up in the light side of KTP crystal, is used for gathering the power of laser; Host computer is connected with power detector; Stepping motor is connected with host computer and rotating device; Temperature controller is connected with host computer and temperature control device. According to the frequency of KTP crystal back end light path that power detector tests, the temperature and rotation angle of crystal seat are generated, and then the best phase matching angle and matching temperature of crystal are obtained by testing. The application proposes a kind of phase matching angle and matching temperature test system for KTP crystal, and the automatic test of phase matching angle and matching temperature can be realized.

Description

Technical Field

[0001] This utility model relates to the field of laser technology, specifically to an automatic testing system for the phase matching angle and matching temperature of a KTP crystal. Background Technology

[0002] In the field of lasers, nonlinear optical frequency conversion and tunable laser technology have always been research hotspots. With the development of laser technology, a number of high-quality nonlinear laser crystals have enabled the rapid development of nonlinear optical frequency conversion and tunable laser technology.

[0003] Currently, commercially available frequency-doubled laser crystals mainly include KDP crystals, LBO crystals, BBO crystals, and KTP crystals. Among them, KDP and LBO crystals have poor frequency doubling effects; BBO crystals have a large walk-off angle, making them unsuitable for strong focusing and exhibiting some deliquescence; CLBO crystals are also prone to deliquescence. KTP crystals, however, can achieve a frequency doubling efficiency of up to approximately 80% for Nd:YAG-pumped 1064nm wavelength lasers. They possess a large effective nonlinear coefficient (approximately 15 times that of KDP crystals), a large allowable angle and allowable temperature, a small walk-off angle, and are non-hygroscopic and non-deliquescent, with a high damage threshold. The high conversion efficiency and relatively low market price of KTP crystals give them an important position in the field of frequency-doubled crystals.

[0004] The phase matching angle and matching temperature of a crystal directly determine its nonlinear frequency conversion efficiency and are core parameters of crystal performance. Measuring the phase matching angle and matching temperature of KTP crystals is of great significance for improving the utilization of KTP crystals. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an automatic testing system for the phase matching angle and matching temperature of KTP crystals.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An automatic testing system for the phase matching angle and matching temperature of a KTP crystal includes:

[0008] Laser emitting unit: used to emit laser light with a wavelength of 1064nm;

[0009] Crystal mount: includes a rotation device and a temperature control device, and a temperature sensor is provided on the crystal mount;

[0010] KTP crystal: disposed on the crystal holder, and the KTP crystal is disposed behind the crystal holder, and the KTP crystal is located in the propagation optical path of the laser;

[0011] Power detector: Located at the rear end of the KTP crystal, on the light-emitting side of the KTP crystal, used to collect the power of the laser.

[0012] Host computer: connected to the power detector;

[0013] Stepper motor: connected to the host computer and the rotating device;

[0014] Temperature controller: connected to the host computer and the temperature control device.

[0015] In some embodiments of this application, the laser emitting unit includes:

[0016] Light source: used to emit collimated red light;

[0017] Reflector: disposed on the light-emitting side of the light source, perpendicular to the propagation direction of the collimated red light;

[0018] Crystal rod: disposed on the light-emitting side of the reflector;

[0019] Output mirror: disposed on the light-emitting side of the crystal rod;

[0020] The KTP crystal is disposed on the light-emitting side of the output mirror.

[0021] In some embodiments of this application, a beam splitter is also included, which is disposed between the KTP crystal and the power detector.

[0022] In some embodiments of this application, the beam splitter is set at a 45° tilt angle, with the propagation direction of the laser as a reference.

[0023] In some embodiments of this application, the side of the beam splitter closest to the KTP crystal is coated with a high-reflectance film and a high-transmittance film.

[0024] In some embodiments of this application, an aperture is also included, disposed between the laser emitting unit and the KTP crystal.

[0025] In some embodiments of this application, the aperture is an adjustable aperture.

[0026] In some embodiments of this application, a beam shrinking lens is also included, disposed between the aperture and the KTP crystal.

[0027] In some embodiments of this application, the beam reducer is coated with an anti-reflective film on the side facing the aperture.

[0028] In some embodiments of this application, the system further includes a data acquisition card connected to the power detector and the host computer.

[0029] Compared with the prior art, the technical advantage of the automatic testing system for phase matching angle and matching temperature of KTP crystal provided by this utility model is that it proposes a testing system for phase matching angle and matching temperature of KTP crystal, which can realize the automatic testing of phase matching angle and matching temperature. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the automatic testing system for KTP crystal phase matching angle and matching temperature in this application;

[0032] In the above figures:

[0033] 1. Light source;

[0034] 2. Reflector;

[0035] 3. Crystal rod;

[0036] 4. Output mirror;

[0037] 5. Aperture;

[0038] 6. Beam shrinking lens;

[0039] 7. KTP crystal

[0040] 8. Beam splitter;

[0041] 9. Power detector;

[0042] 10. Stepper motor;

[0043] 11. Temperature controller;

[0044] 12. Data acquisition card;

[0045] 13. Host computer. Detailed Implementation

[0046] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0047] It should be noted that when a component is referred to as "set on" or "connected to" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0048] It should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0049] The terms "first" and "second" are used for descriptive purposes only and are not intended to imply relative importance.

[0050] The phase matching angle and matching temperature of a crystal directly determine its nonlinear frequency conversion efficiency and are the core parameters of crystal performance.

[0051] The phase-matching angle, the angle required to make the refractive indices of the fundamental frequency light and the harmonic light (or sum / difference frequency light) equal, determines whether efficient conversion is possible. The matching temperature of the crystal, achieved by temperature-tuning the crystal's refractive index to re-satisfy the phase-matching condition, determines whether efficient conversion is stable. The phase-matching angle determines the peak efficiency, while the matching temperature determines whether the peak efficiency can be maintained. Together, they constitute a "two-dimensional window" of crystal performance; deviation from either parameter will result in a precipitous drop in efficiency, stability, and beam quality.

[0052] To measure the phase matching angle and matching temperature of a crystal, this application proposes an automatic testing system for the phase matching angle and matching temperature of a KTP crystal.

[0053] An automatic testing system for phase matching angle and matching temperature of KTP crystal, the structure of which is referenced. Figure 1 .

[0054] The laser emitting unit is used to emit laser light with a wavelength of 1064nm.

[0055] In some embodiments of this application, the laser emitting unit specifically comprises: a light source 1, a reflector 2, a crystal rod 3, and an output mirror 4.

[0056] Light source 1 is used to emit collimated red light.

[0057] Reflector 2 is positioned on the light-emitting side of light source 1, perpendicular to the direction of propagation of the collimated red light. Reflector 2 transforms the diverging beam into parallel (or nearly parallel) light, thereby improving the directionality of the optical path, energy utilization, and the imaging / measurement accuracy of subsequent optical systems. The red light emitted by light source 1, after passing through reflector 2, exhibits less diffusion and higher energy concentration.

[0058] The crystal rod 3 is disposed on the light-emitting side of the reflector 2. In this embodiment, an Nd:YAG crystal rod 3 is used as the core gain medium of the solid-state laser. The length direction of the crystal rod 3 is parallel to the propagation direction of the collimated light, and the collimated light continues to propagate towards the rear end after passing through the crystal rod 3.

[0059] Output mirror 4 is located on the light-emitting side of crystal rod 3; output mirror 4 is a key mirror in the laser resonant cavity for controlling the output of light. It reflects part of the light and transmits part of the light. The reflectivity is typically 70%–95% (depending on the type of laser), feeding a portion of the light back into the cavity for further stimulation and amplification, while allowing the remaining portion to be transmitted as usable laser output. The output light from crystal rod 3 continues to propagate towards the rear end after passing through output mirror 4.

[0060] The reflector 2, the Nd:YAG crystal rod 3, and the output mirror 4 form a 1064nm laser oscillator, which outputs a 1064nm wavelength laser.

[0061] KTP crystal 7 is located on the light-emitting side of output mirror 5. The angle and temperature of KTP crystal 7 relative to the collimated light can affect the frequency of the collimated light emitted after passing through KTP crystal 7.

[0062] To test the effects of different angles and temperatures on the emitted light frequency, a KTP crystal 7 was placed on a crystal holder, positioned behind the holder and along the laser's propagation path. The crystal holder provides orientation for the KTP crystal.

[0063] The crystal holder includes a rotation mechanism and a temperature control mechanism, and a temperature sensor is installed on the crystal holder. Rotating the crystal holder allows adjustment of the angle of the KTP crystal 7 relative to the collimated light; furthermore, the crystal holder can be adjusted in multiple dimensions. Adjusting the temperature control mechanism allows adjustment of the crystal holder's temperature, thereby controlling the temperature of the KTP crystal 7 mounted on the crystal holder. The rotation mechanism and temperature control mechanism of the crystal holder are existing technologies and will not be described in detail here.

[0064] A power detector 9 is located at the rear end of the KTP crystal, on the light-emitting side, and is used to collect the laser power. Specifically, in this embodiment, the power detector 9 is used to measure the power of a frequency-doubled 532nm laser. The power value of light is a numerical value that reflects the magnitude of the light's "energy flow." By measuring the light power value of a KTP crystal 7 at a set angle and temperature, the matching angle and matching temperature of the KTP crystal 7 can be determined.

[0065] The host computer 13 is connected to the power detector 10; the power value collected by the power detector 10 is transmitted to the host computer 13. The host computer 13 can generate adjustment signals for the angle and temperature of the KTP crystal 7 based on the power value. To facilitate signal acquisition, the system also includes a data acquisition card 12, which is connected to the power detector 9 and the host computer 13. The data acquisition card 12 assists in the acquisition of power signals.

[0066] Stepper motor 10 is connected to host computer 13 and rotating device; stepper motor 10 receives angle adjustment signal and adjusts the angle of crystal holder by step adjustment, thereby adjusting the angle of KTP crystal 7 relative to collimated light. Temperature controller 11 is connected to host computer 13 and temperature control device. Temperature controller 11 receives temperature adjustment signal and controls the temperature of crystal holder, thereby adjusting the temperature of KTP crystal 7.

[0067] In some embodiments of this application, an aperture 5 is further included, disposed between the laser emitting unit and the KTP crystal 7. The aperture 5 is an adjustable aperture. An adjustable aperture can reduce stray light and control the shape and direction of the light beam.

[0068] In some embodiments of this application, a beam shrinking lens 6 is also included, disposed between the aperture 5 and the KTP crystal 7. In this embodiment, the beam shrinking lens 6 has a size of φ12.7mm and a focal length f = 500mm. The side of the beam shrinking lens facing the aperture 5 is coated with an anti-reflection film for 1064nm, increasing the transmittance of 1064nm laser light and simultaneously adjusting the laser spot size.

[0069] Aperture 5 and beam shrinker 6 shape the output 1064nm laser to obtain the required 1064nm beam. KTP crystal 7 frequency doubles the 1064nm laser passing through beam shrinker 6 to generate 532nm green light mixed with 1064nm. Beam splitter 8 filters out the excess 1064nm light, allowing only the 532nm green light to pass through. The 532nm green light is received by power detector 9, and the collected data is transmitted to acquisition card 12.

[0070] In some embodiments of this application, a beam splitter 8 is also included, which is disposed between the KTP crystal 7 and the power detector 9.

[0071] In some embodiments of this application, the beam splitter 8 is tilted at a 45° angle with respect to the direction of laser propagation. In some embodiments of this application, the side of the beam splitter 8 closest to the KTP crystal 7 is coated with a high-reflection film and a high-transmittance film.

[0072] Specifically, the beam splitter 8 is a 45° beam splitter 8. Its end face close to the KTP crystal 7 is coated with a high reflectivity film for 1064nm and a high transmittance film for 532nm, which reflects excess 1064nm laser and improves the transmittance of 532nm laser; its end face away from the KTP crystal 7 is coated with an antireflection film for 532nm, which also improves the transmittance of 532nm laser.

[0073] The testing system provided in this application can gradually find the optimal matching angle and temperature based on the feedback optical power value by adjusting the angle and temperature of the KTP crystal, thus achieving automatic testing of the optimal matching angle and temperature. For example, the optimal matching angle of the KTP crystal 7 at a certain temperature can be found by fixing the temperature; or the optimal matching temperature at a certain angle can be found by fixing the angle.

[0074] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A KTP crystal phase matching angle and matching temperature automatic testing system, characterized in that, include: Laser emitting unit: used to emit laser light with a wavelength of 1064nm; Crystal mount: includes a rotation device and a temperature control device, and a temperature sensor is provided on the crystal mount; KTP crystal: disposed on the crystal holder, and the KTP crystal is disposed behind the crystal holder, and the KTP crystal is located in the propagation optical path of the laser; Power detector: Located on the light-emitting side of the KTP crystal, used to collect the power of the laser; Host computer: connected to the power detector; Stepper motor: connected to the host computer and the rotating device; Temperature controller: connected to the host computer and the temperature control device.

2. The KTP crystal phase matching angle and matching temperature automatic test system according to claim 1, characterized in that, The laser emitting unit includes: Light source: used to emit collimated red light; Reflector: disposed on the light-emitting side of the light source, perpendicular to the propagation direction of the collimated red light; Crystal rod: disposed on the light-emitting side of the reflector; Output mirror: disposed on the light-emitting side of the crystal rod; The KTP crystal is disposed on the light-emitting side of the output mirror.

3. The KTP crystal phase matching angle and matching temperature automatic test system according to claim 1, characterized in that, It also includes a beam splitter disposed between the KTP crystal and the power detector.

4. The automatic testing system for KTP crystal phase matching angle and matching temperature according to claim 3, characterized in that, The beam splitter is set at a 45° tilt angle, with the propagation direction of the laser as the reference.

5. The KTP crystal phase matching angle and matching temperature automatic test system according to claim 3, characterized in that, The side of the beam splitter closest to the KTP crystal is coated with a high-reflection film and a high-transmittance film.

6. The KTP crystal phase matching angle and matching temperature automatic test system according to claim 1, characterized in that, It also includes an aperture, which is disposed between the laser emitting unit and the KTP crystal.

7. The automatic testing system for KTP crystal phase matching angle and matching temperature according to claim 6, characterized in that, The aperture is an adjustable aperture.

8. The automatic testing system for KTP crystal phase matching angle and matching temperature according to claim 6 or 7, characterized in that, It also includes a beam shrinking mirror, which is disposed between the aperture and the KTP crystal.

9. The KTP crystal phase matching angle and matching temperature automatic test system according to claim 8, characterized in that, The side of the beam reducer facing the aperture is coated with an anti-reflective coating.

10. The automatic testing system for KTP crystal phase matching angle and matching temperature according to claim 1, characterized in that, The system also includes a data acquisition card, which is connected to the power detector and the host computer.

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