System and method for testing fineness of high-reflectivity lens

Abstract

The invention discloses a fineness test system and test method for a high-reflectivity lens, which can be applied to the technical field of optical measurement, and the system comprises a light generation module, a light detection module, a control module and a test module, the light generation module is used for generating tunable incident laser emitted to the to-be-detected lens group; transmission laser is formed after passing through the to-be-measured lens group; the optical detection module is arranged on an optical path of transmission laser and is used for determining corresponding output voltage and laser transmission power; the control module can control the light generation module not to emit the tunable incident laser and trigger the test module to test when the laser transmission power is the strongest; and the test module is connected with the optical detection module and is used for determining ring-down time according to the output voltage of the optical detection module and determining the fineness of the lens according to the ring-down time. In this way, traditional manual testing is replaced with an automatic testing mode, and the testing efficiency can be improved while the testing accuracy is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of optical measurement technologies, and particularly to a fineness test system and method for a high-reflectivity lens. Background Art

[0002] A high-reflectivity lens is a lens with a special multi-layer optical coating on its surface. Its main feature is to strongly reflect incident light like a mirror, which can significantly reduce the stimulation of strong light and glare to the eyes and improve visual comfort. Fineness is one of the important indicators to measure the performance of a reflector, and it can reflect the ability of a high-reflectivity lens to select and enhance light of a specific frequency.

[0003] For high-reflectivity lenses, the cavity ring-down method is generally used to measure their fineness. Traditional fineness test methods for high-reflectivity lenses rely on the experience and skills of operators, and it is extremely easy to introduce operation errors during the manual light interruption process, which easily leads to problems of low test accuracy and low test efficiency.

[0004] Therefore, how to improve the test efficiency while ensuring test accuracy is an urgent problem for those skilled in the art. Summary of the Invention

[0005] Based on the above problems, the present application provides a fineness test system and method for a high-reflectivity lens. By replacing the traditional manual test with an automated test method, it can improve the test efficiency while ensuring test accuracy.

[0006] In a first aspect, an embodiment of the present application provides a fineness test system for a high-reflectivity lens, including: a light generation module, a light detection module, a control module, and a test module;

[0007] The light generation module is configured to generate tunable incident laser light and direct the tunable incident laser light towards a lens group to be tested; the lens group to be tested includes a pair of lenses with high-reflective surfaces facing inward; the frequency change range of the tunable incident laser light covers the free spectral range of the lens group to be tested;

[0008] The tunable incident laser light passes through the lens group to be tested to form transmitted laser light;

[0009] The light detection module is arranged on the optical path of the transmitted laser light and is configured to receive the transmitted laser light and determine the output voltage and laser transmission power corresponding to the transmitted laser light;

[0010] The control module is respectively connected to the light generation module, the light detection module, and the test module, and is configured to control the light generation module not to emit the tunable incident laser light and trigger the test module to perform a test when the laser transmission power is the strongest;

[0011] The test module is connected to the optical detection module, and is configured to determine the ring-down time according to the output voltage of the optical detection module, and determine the fineness of the lens according to the ring-down time.

[0012] Optionally, the light generation module includes: a narrow linewidth laser and a DA converter;

[0013] The narrow linewidth laser is configured to generate an initial laser;

[0014] The DA converter is connected to the narrow linewidth laser, and is configured to control the initial laser to generate a frequency change, and form a tunable incident laser.

[0015] Optionally, the system further includes: a collimator;

[0016] The collimator is disposed on the optical path of the tunable incident laser, and is configured to modulate the propagation direction of the tunable incident laser.

[0017] Optionally, the optical detection module includes: a photodetector and an AD sampling module;

[0018] The photodetector is disposed on the optical path of the transmitted laser, and is configured to determine the output voltage corresponding to the transmitted laser;

[0019] The AD sampling module is connected to the photodetector, and is configured to determine the laser transmission power corresponding to the transmitted laser according to the output voltage.

[0020] Optionally, the system further includes: a quarter-wave plate;

[0021] The quarter-wave plate is disposed in the optical path of the tunable incident laser, and is configured to modulate the tunable incident laser from linearly polarized light to circularly polarized light.

[0022] Optionally, the control module includes: an MCU control, a radio frequency switch, and an acousto-optic modulator;

[0023] The acousto-optic modulator is disposed in the optical path of the tunable incident laser, and the radio frequency switch is connected to the acousto-optic modulator; the opening and closing of the radio frequency switch respectively control whether the acousto-optic modulator shoots the tunable incident laser at the lens group to be measured;

[0024] The MCU control is respectively connected to the AD sampling module and the radio frequency switch, and is configured to control the radio frequency switch to turn off when the laser transmission power is the strongest.

[0025] Optionally, the system further includes: an optical power detection module;

[0026] The optical power detection module includes: an optical circulator and an optical power meter;

[0027] The optical circulator is arranged in the optical path of the tunable incident laser, and is used to receive the reflected light of the lens and direct the reflected light to the optical power meter;

[0028] The optical power meter is connected to the optical circulator, and is used to receive the reflected light and determine the reflection power corresponding to the reflected light.

[0029] Optionally, the system further includes: a first mirror, a second mirror, and a third mirror;

[0030] The first mirror and the second mirror are sequentially arranged in the optical path of the tunable incident laser, and are used to direct the tunable incident laser to the lens group to be measured through cooperation;

[0031] The third mirror is arranged in the optical path of the transmitted laser, and is used to direct the transmitted laser to the optical detection module.

[0032] Optionally, the system further includes: a first lens;

[0033] The first lens is arranged in the optical path of the transmitted laser, and is used to converge the transmitted laser to the test module.

[0034] In a second aspect, an embodiment of the present application provides a test method for a fineness test system of a high-reflectivity lens. The system includes an optical generation module, an optical detection module, a control module, and a test module; the method includes:

[0035] Configure the optical generation module, the optical detection module, the control module, and the test module so that the optical generation module can generate a tunable incident laser and emit it to the lens group to be measured; the lens group to be measured includes a pair of lenses with high-reflectivity surfaces facing inward; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be measured;

[0036] Determine the output voltage and the laser transmission power of the transmitted laser generated by the tunable incident laser passing through the lens group to be measured;

[0037] When the laser transmission power is the strongest, control the optical generation module not to emit the tunable incident laser, and use the test module to determine the decay time corresponding to the output voltage;

[0038] Determine the fineness of the lens based on the decay time.

[0039] It can be seen from the above technical solutions that compared with the prior art, the present application has the following advantages:

[0040] The fineness test system for high reflectivity lenses provided by this application includes: a light generation module, a light detection module, a control module, and a test module. Among them, the light generation module is used to generate tunable incident laser and shoot the tunable incident laser towards the lens group to be tested. The lens group to be tested includes a pair of lenses with high reflectivity facing inwards; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be tested. The tunable incident laser passes through the lens group to be tested to form transmitted laser; the light detection module is arranged on the optical path of the transmitted laser and is used to receive the transmitted laser and determine the output voltage and laser transmission power corresponding to the transmitted laser. The control module is respectively connected to the light generation module, the light detection module, and the test module, and is used to control the light generation module not to emit tunable incident laser and trigger the test module to perform a test when the laser transmission power is the strongest. The test module is connected to the light detection module and is used to determine the decay time according to the output voltage of the light detection module and determine the fineness of the lens according to the decay time. In this way, by replacing the traditional manual test with an automated test method, the test efficiency can be improved while ensuring the test accuracy. Description of the Drawings

[0041] Figure 1 It is a schematic diagram of a fineness test system provided by an embodiment of this application;

[0042] Figure 2 It is a schematic diagram of a light generation module provided by an embodiment of this application;

[0043] Figure 3 It is a schematic diagram of a collimator provided by an embodiment of this application;

[0044] Figure 4 It is a schematic diagram of a light detection module provided by an embodiment of this application;

[0045] Figure 5 It is a schematic diagram of a quarter-wave plate provided by an embodiment of this application;

[0046] Figure 6 It is a schematic diagram of a reflector provided by an embodiment of this application;

[0047] Figure 7 It is a schematic diagram of a first lens provided by an embodiment of this application;

[0048] Figure 8 It is a schematic diagram of a control module provided by an embodiment of this application;

[0049] Figure 9 It is a schematic diagram of a light power detection module provided by an embodiment of this application;

[0050] Figure 10Flow chart of a test method for a fineness test system for high-reflectivity lenses provided by an embodiment of the present application. Detailed implementation manners

[0051] As described above, the existing fineness test methods for high-reflectivity lenses have problems of low test accuracy and low test efficiency. Specifically, it is difficult to measure the exact value of the reflectivity of lenses with particularly high reflectivity by methods other than cavity ring-down. Moreover, there are many drawbacks in the traditional fineness test methods for high-reflectivity lenses. Among them, the manual test method highly depends on the experience and skills of operators, not only with low efficiency, but also prone to inaccurate test results caused by human factors.

[0052] To solve the above problems, the present application provides a fineness test system for high-reflectivity lenses, including: a light generation module, a light detection module, a control module, and a test module. Among them, the light generation module is used to generate tunable incident laser and direct the tunable incident laser towards the lens group to be tested. The lens group to be tested includes a pair of lenses with high-reflective surfaces facing inwards; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be tested. The tunable incident laser passes through the lens group to be tested to form transmitted laser; the light detection module is arranged on the optical path of the transmitted laser, and is used to receive the transmitted laser and determine the output voltage and laser transmission power corresponding to the transmitted laser. The control module is respectively connected to the light generation module, the light detection module, and the test module, and is used to control the light generation module not to emit tunable incident laser when the laser transmission power is the strongest, and trigger the test module to perform a test. The test module is connected to the light detection module, and is used to determine the decay time according to the output voltage of the light detection module, and determine the fineness of the lens according to the decay time.

[0053] In this way, by replacing the traditional manual test with an automated test method, the test efficiency can be improved while ensuring the test accuracy.

[0054] It should be noted that a fineness test system and a test method for high-reflectivity lenses provided by the present application can be applied to the field of optical measurement technology. The above is only an example, and does not limit the application field of a fineness test system and a test method for high-reflectivity lenses provided by the present application.

[0055] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0056] Figure 1 Schematic diagram of a fineness test system provided by an embodiment of the present application. In combination with Figure 1 As shown, the system includes:

[0057] An optical generation module 100, an optical detection module 200, a control module 300, and a test module 400;

[0058] The optical generation module 100 is used to generate tunable incident laser light and direct the tunable incident laser light towards the lens group to be tested; the lens group to be tested includes a pair of lenses with high reflectivity facing inwards; the frequency change range of the tunable incident laser light covers the free spectral range of the lens group to be tested;

[0059] The tunable incident laser light passes through the lens group 500 to be tested to form transmitted laser light;

[0060] The optical detection module 200 is arranged on the optical path of the transmitted laser light and is used to receive the transmitted laser light and determine the output voltage and laser transmission power corresponding to the transmitted laser light;

[0061] The control module 300 is respectively connected to the optical generation module 100, the optical detection module 200, and the test module 400, and is used to control the optical generation module 100 not to emit the tunable incident laser light when the laser transmission power is the strongest, and trigger the test module 400 to perform a test;

[0062] The test module 400 is connected to the optical detection module 200 and is used to determine the ring-down time according to the output voltage of the optical detection module 200 and determine the fineness of the lens according to the ring-down time.

[0063] Specifically, two identical lenses to be measured can be placed on a device with a high degree of parallelism, with the high-reflection surface facing inward. The laser frequency incident on the front-end high-reflectivity lens is scanned, and the intensity of the light transmitted through the rear-end high-reflectivity lens is observed to determine the cavity frequency resonance formed by the laser and the two lenses to be measured. Then, the finesse of the lenses to be measured can be accurately obtained in combination with the cavity ring-down principle. It can be understood that the light generation module 100 can generate tunable incident laser light and vertically incident it on the lens group 500 to be measured composed of two lenses to be measured, and the frequency change range of the tunable incident laser light incident on the lens group 500 to be measured covers the free spectral range of the lens group 500 to be measured. The transmitted laser light formed by the tunable incident laser light passing through the lens group 500 to be measured is vertically incident on the light detection module 200, and the light detection module 200 receives and determines its corresponding output voltage and laser transmission power (both of which change with the change of the laser frequency). When the light detection module 200 determines that the laser transmission power is the strongest at a certain moment, it sends a signal to the control module 300, and the control module 300 controls the light generation module 100 not to emit tunable incident laser light to the lens group 500 to be measured. The light interruption process delay is on the order of nanoseconds (ns). At the same time, a test request is sent to the test module 400. After receiving the test request, the test module 400 can determine the ring-down time based on the output voltage after light interruption determined by the light detection module 200, and then determine the finesse of the lens based on the ring-down time. In addition, the test module includes an oscilloscope and a calculator. The oscilloscope is used to sample the optical ring-down waveform data corresponding to the output voltage after light interruption, and the calculator is used to analyze and calculate the optical ring-down waveform data sampled by the oscilloscope to determine the ring-down time, and then determine the finesse of the lens.

[0064] Figure 2 Schematic diagram of a light generation module provided by an embodiment of the present application. In combination with Figure 2 As shown, the light generation module 100 includes: a narrow linewidth laser 110 and a DA converter 120;

[0065] The narrow linewidth laser 110 is used to generate initial laser light;

[0066] The DA converter 120 is connected to the narrow linewidth laser 110 and is used to control the initial laser light to generate a frequency change to form tunable incident laser light.

[0067] Specifically, the narrow linewidth laser 110 is a single-frequency coherent light source with an extremely narrow spectral linewidth and can generate narrow linewidth incident laser light. The control module 300 is connected to a digital-to-analog (DA) converter, and the DA converter 120 is in turn connected to the narrow linewidth laser 110. The control module 300 can control the DA converter 120 to scan the frequency of the narrow linewidth laser 110, so that the frequency of the incident laser light changes, and form tunable incident laser light that is vertically incident on the lens group 500 to be measured.

[0068] Figure 3 This is a schematic diagram of a collimator provided by an embodiment of the present application. In combination with Figure 3 As shown, the system further includes: a collimator 600;

[0069] The collimator 600 is arranged on the optical path of the tunable incident laser and is used for modulating the propagation direction of the tunable incident laser.

[0070] Specifically, the collimator 600 is arranged between the narrow linewidth laser 110 and the lens group 500 to be measured on the optical path of the tunable incident laser, and can collimate the tunable incident laser.

[0071] Figure 4 This is a schematic diagram of an optical detection module provided by an embodiment of the present application. In combination with Figure 4 As shown, the optical detection module 200 includes: a photodetector 210 and an AD sampling module 220;

[0072] The photodetector 210 is arranged on the optical path of the transmitted laser and is used for determining the output voltage corresponding to the transmitted laser;

[0073] The AD sampling module 220 is connected to the photodetector 210 and is used for determining the laser transmission power corresponding to the transmitted laser according to the output voltage.

[0074] Specifically, the transmitted laser is vertically incident on the photodetector 210. The photodetector 210 can determine its output voltage, and divide the output voltage into two paths. One path is output to the analog-to-digital (AD) sampling module to judge the laser transmission power corresponding to the transmitted laser, and the other path is output to the test module 400 for testing.

[0075] Figure 5 This is a schematic diagram of a quarter-wave plate provided by an embodiment of the present application. In combination with Figure 5 As shown, the system further includes: a quarter-wave plate 700;

[0076] The quarter-wave plate 700 is arranged in the optical path of the tunable incident laser and is used for modulating the tunable incident laser from linearly polarized light to circularly polarized light.

[0077] Specifically, the quarter-wave plate 700 is arranged between the collimator 600 and the lens group 500 to be measured in the optical path of the tunable incident laser, and can modulate the tunable incident laser from linearly polarized light to circularly polarized light.

[0078] Figure 6 This is a schematic diagram of a mirror provided by an embodiment of the present application. In combination with Figure 6As shown, the system further includes: a first mirror 810, a second mirror 820, and a third mirror 830;

[0079] The first mirror 810 and the second mirror 820 are sequentially arranged in the optical path of the tunable incident laser, and are used to direct the tunable incident laser to the lens group 500 to be measured through cooperation;

[0080] The third mirror 830 is arranged in the optical path of the transmitted laser, and is used to direct the transmitted laser to the optical detection module 200.

[0081] Specifically, in order to better design the system structure and save space, mirrors can be introduced to adjust the optical path. Among them, the first mirror 810 and the second mirror 820 are sequentially arranged between the collimator 600 and the quarter-wave plate 700 in the optical path of the tunable incident laser. Based on the reflection principle, the optical path of the tunable incident laser can be changed, saving lateral space, and the tunable incident laser can be directed to the lens group 500 to be measured through cooperation. In addition, the third mirror 830 is arranged between the lens group 500 to be measured and the photodetector 210 in the optical path of the transmitted laser, which also plays a role in saving lateral space. Based on the reflection principle, the optical path of the transmitted laser is changed, and the transmitted laser is vertically incident into the photodetector 210.

[0082] Figure 7 It is a schematic diagram of a first lens provided by an embodiment of the present application. Combining Figure 7 As shown, the system further includes: a first lens 900;

[0083] The first lens 900 is arranged in the optical path of the transmitted laser, and is used to converge the transmitted laser to the test module 400.

[0084] Specifically, the first lens 900 is arranged between the lens group 500 to be measured and the third mirror 830 in the optical path of the transmitted laser, and can cooperate with the third mirror 830 to focus the transmitted laser into the photodetector 210.

[0085] Figure 8 It is a schematic diagram of a control module provided by an embodiment of the present application. Combining Figure 8 As shown, the control module 300 includes: an MCU control 310, a radio frequency switch 320, and an acousto-optic modulator 330;

[0086] The acousto-optic modulator 330 is arranged in the optical path of the tunable incident laser, and the radio frequency switch 320 is connected to the acousto-optic modulator 330; the opening and closing of the radio frequency switch 320 respectively control whether the acousto-optic modulator 330 shoots the tunable incident laser towards the lens group 500 to be measured;

[0087] The MCU control 310 is respectively connected to the AD sampling module 220 and the RF switch 320, and is used to control the RF switch 320 to close when the laser transmission power is the strongest.

[0088] Specifically, the microcontroller unit (MCU) control, that is, the MCU control 310 is connected to the AD sampling module 220, DA conversion, test module 400, and RF switch 320, and can control the RF switch 320 based on the laser transmission power determined by the AD sampling module 220. The RF switch 320 is connected to the acousto-optic modulator 330, and the acousto-optic modulator 330 accesses the tunable incident laser and is disposed between the narrow linewidth laser 110 and the collimator 600. When the AD sampling module 220 determines that the laser transmission power of the transmitted laser is the strongest at the current moment, the MCU control 310 sends a light path closing signal to the RF switch 320. After receiving the light path closing signal, the RF switch 320 enters the closed state, and further controls the acousto-optic modulator 330 to be unable to shoot the tunable incident laser towards the lens group to be measured 500. On the contrary, when the laser transmission power of the transmitted laser is not the strongest, the RF switch 320 is in the open state, and the acousto-optic modulator 330 can normally shoot the tunable incident laser towards the lens group to be measured 500.

[0089] In addition, the system may further include an RF driver 340. The RF driver is connected to the RF switch 320 and can independently control the opening and closing of the RF switch 320.

[0090] Figure 9 It is a schematic diagram of an optical power detection module provided by an embodiment of the present application. Combining Figure 9 As shown, the system further includes: an optical power detection module;

[0091] The optical power detection module specifically includes: an optical circulator 1010 and an optical power meter 1020;

[0092] The optical circulator 1010 is disposed in the optical path of the tunable incident laser and is used to receive the reflected light of the lens and direct the reflected light to the optical power meter 1020;

[0093] The optical power meter 1020 is connected to the optical circulator 1010 and is used to receive the reflected light and determine the reflection power corresponding to the reflected light.

[0094] Specifically, the optical circulator 1010 is disposed between the AOM 330 and the narrow linewidth laser 110, in the optical path of the tunable incident laser, does not affect the optical path of the tunable incident laser, and can receive the tunable incident laser generated by the narrow linewidth laser 110 and output it to the AOM 330. In addition, the optical circulator 1010 can also collect the laser (reflected light) reflected back from the lens group 500 to be tested, and guide it to the optical power meter 1020. The optical power meter 1020 is connected to the optical circulator 1010, and can determine the corresponding reflected power through the reflected light, thereby determining the optical path conditions. For example, assuming that the output frequency of the narrow linewidth laser 110 is The laser with a power of 1mW passes through the 1550nm optical circulator 1010 and the acousto-optic modulator 330 used as an optical switch, and then enters the spatial optical path through the 1550nm fiber collimator 600. Before installing the high-reflectivity lens, first adjust the height and angle of the spatial optical path device in combination with the AD sampling module 220 so that the laser can be incident on the photodetector 210 and its output is maximized under the premise of not being saturated. Further, the optical power detection module is connected to the optical path, and the rear-end high-reflectivity lens (the lens to be tested at the far end) is first installed. By adjusting the mirror frame of the first reflector 810 and the second reflector 820, the adjustment is completed when the reflected power of the reflected light measured by the optical power meter 1020 is greater than 0.5mW. Further, the front-end high-reflectivity lens (the lens to be tested at the near end) is installed and its mirror frame is adjusted. When the reflected power of the reflected light is observed to be greater than 0.5mW during the adjustment process, the adjustment is completed. At this point, the entire system configuration is completed, and the fineness test of the lens to be tested can be carried out.

[0095] In summary, the fineness test system of the high reflectivity lens provided by the present application includes: a light generating module, a light detecting module, a control module and a test module. Among them, the light generating module is used to generate a tunable incident laser and emit the tunable incident laser to the lens group to be tested. The lens group to be tested includes a pair of lenses with high reflection faces facing inward; the frequency variation range of the tunable incident laser covers the free spectrum area of the lens group to be tested. The tunable incident laser passes through the lens group to be tested to form a transmitted laser; the light detecting module is arranged on the optical path of the transmitted laser, and is used to receive the transmitted laser and determine the output voltage and laser transmission power corresponding to the transmitted laser. The control module is connected to the light generating module, the light detecting module and the test module respectively, and is used to control the light generating module not to emit the tunable incident laser when the laser transmission power is the strongest, and trigger the test module to perform the test. The test module is connected to the light detecting module, and is used to determine the ring-down time according to the output voltage of the light detecting module, and determine the fineness of the lens according to the ring-down time. In this way, the traditional manual test is replaced by the automated test method, which can improve the test efficiency while ensuring the test accuracy.

[0096] Figure 10 The flowchart of a test method for a fineness test system of a high reflectivity lens provided by an embodiment of this application. In combination with Figure 10 As shown, the method may include:

[0097] S1: Configure the light generation module, the light detection module, the control module, and the test module, so that the light generation module can generate tunable incident laser and emit it towards the lens group to be tested; the lens group to be tested includes a pair of lenses with high reflective surfaces facing inwards; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be tested.

[0098] In practical applications, in combination with the above system configuration, first, in combination with the AD sampling module, adjust the height and angle of the spatial optical path device, so that the tunable incident laser generated by the light generation module can be incident on the photodetector and make its output maximum on the premise of not being saturated. Then, in combination with the optical power detection module, install the lens to be tested at the far end and the lens to be tested at the near end successively, and adjust their lens mounts to complete the calibration of the entire optical path. Continuing with the example of a narrow linewidth laser outputting laser with a frequency of 1 mW and a power of 1 mW, assuming the two lenses to be tested are 6 cm apart, the free spectral range is 2.5 GHz, and the frequency change of the corresponding narrow linewidth laser is above 2.5 GHz. Specifically, the free spectral range is also called the longitudinal mode interval of the F-P cavity. The expression for the free spectral range is as follows: ; where c (about 3×10 8 m / s) is the propagation speed of light in air, n (about 1) is the refractive index of light in air, and L is the cavity length of the F-P cavity formed by the two lenses to be tested. The frequency change of the narrow linewidth laser can be controlled by the voltage of the piezoelectric ceramic PZT (lead zirconate titanate). Automatically scan the PZT voltage to change the laser output frequency, so that it sweeps through a range of 2.5 GHz from high to low at a scanning frequency of 2 MHz / ms.

[0099] S2: Determine the output voltage and laser transmission power of the transmitted laser generated by the tunable incident laser passing through the lens group to be tested.

[0100] In practical applications, during the scanning process, the AD sampling module monitors the output voltage of the photodetector in real time, and determines the maximum output voltage Vmax and its corresponding laser transmission power, and records the voltage Vpzt of the scanning PZT at this time. After the scanning ends, the voltage of the PZT needs to be set to Vpzt - 0.2V, because there is hysteresis when adjusting the PZT, so it needs to be called back, so that the frequency difference between the callback position and the just-recorded position is between 100 MHz and 150 MHz.

[0101] S3: When the laser transmission power is the strongest, control the light generation module not to emit the tunable incident laser, and use the test module to determine the decay time corresponding to the output voltage.

[0102] In practical applications, continuing with the above example, continue to scan the frequency from high to low at a rate of 2 MHz / ms. When the AD sampling module determines that the output voltage of the photodetector reaches 95% of Vmax, use the MCU to control and send a signal to the RF switch to control the RF switch to close, and at the same time automatically cut off the RF power of the acousto-optic modulator. It can be understood that the entire light cutoff process is completed by a high-speed RF switch (with a delay in the order of ns) and a high-speed optical switch (i.e., the acousto-optic modulator, with a delay in the order of ns). At the same time, the output high level is used as the light cutoff trigger signal for the oscilloscope (with a rising edge in the order of 10 ns). Starting from when the oscilloscope receives the light cutoff trigger signal, determine the light decay waveform corresponding to the output voltage, and then calculate the decay time through a calculator. Specifically, the time when the output voltage drops to 1 / e of the highest value (e is the base of the natural logarithm) can be recorded as the decay time of the F-P cavity formed by the lens group to be measured.

[0103] S4: Determine the fineness of the lens based on the decay time.

[0104] In practical applications, the fineness of the lens can be calculated in combination with the fineness calculation formula. Among them, the fineness calculation formula is , assuming the decay time is 35.2 us, then according to the formula, the fineness of the lens to be measured can be calculated to be approximately 552920. In the formula is the fineness, is the pi, is the decay time, is the free spectral range.

[0105] In summary, a test method for a fineness test system of a high-reflectivity lens provided by the present application includes configuring a light generation module, a light detection module, a control module, and a test module, enabling the light generation module to generate a tunable incident laser and emit it towards the lens group to be measured; the lens group to be measured includes a pair of lenses with high reflectivity facing inward; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be measured; determine the output voltage and laser transmission power of the transmitted laser generated by the tunable incident laser passing through the lens group to be measured; when the laser transmission power is the strongest, control the light generation module not to emit the tunable incident laser, and use the test module to determine the decay time corresponding to the output voltage; determine the fineness of the lens based on the decay time. In this way, by replacing the traditional manual test with an automated test method, the test efficiency can be improved while ensuring the test accuracy.

[0106] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fineness test system for a high reflectivity lens, characterized in that, The system includes: an optical generation module, an optical detection module, a control module, and a test module; The optical generation module is configured to generate tunable incident laser light and direct the tunable incident laser light towards a lens group to be measured; the lens group to be measured includes a pair of lenses with high-reflection surfaces facing inwards; the frequency variation range of the tunable incident laser light covers the free spectral range of the lens group to be measured; The tunable incident laser light passes through the lens group to be measured to form transmitted laser light; The optical detection module is disposed on the optical path of the transmitted laser light and is configured to receive the transmitted laser light and determine the output voltage and laser transmission power corresponding to the transmitted laser light; The control module is respectively connected to the optical generation module, the optical detection module, and the test module, and is configured to, when the laser transmission power is the strongest, control the optical generation module not to emit the tunable incident laser light and trigger the test module to perform a test; The test module is connected to the optical detection module and is configured to determine the decay time based on the output voltage of the optical detection module and determine the fineness of the lens based on the decay time.

2. The fineness test system for the high reflectivity lens according to claim 1, characterized in that, The optical generation module includes: a narrow-linewidth laser and a DA converter; The narrow-linewidth laser is configured to generate initial laser light; The DA converter is connected to the narrow-linewidth laser and is configured to control the initial laser light to generate a frequency change to form tunable incident laser light.

3. The fineness test system for a high reflectivity lens according to claim 1, characterized in that, The system further includes: a collimator; The collimator is disposed on the optical path of the tunable incident laser light and is configured to modulate the propagation direction of the tunable incident laser light.

4. The fineness test system for the high reflectivity lens according to claim 1, characterized in that, The optical detection module includes: a photodetector and an AD sampling module; The photodetector is disposed on the optical path of the transmitted laser light and is configured to determine the output voltage corresponding to the transmitted laser light; The AD sampling module is connected to the photodetector and is configured to determine the laser transmission power corresponding to the transmitted laser light based on the output voltage.

5. The fineness test system for a high reflectivity lens according to claim 1, characterized in that, The system further includes: a quarter-wave plate; The quarter-wave plate is disposed in the optical path of the tunable incident laser light and is configured to modulate the tunable incident laser light from linearly polarized light to circularly polarized light.

6. The fineness test system for a high reflectivity lens according to claim 4, characterized in that, The control module includes: an MCU control, a radio frequency switch, and an acousto-optic modulator; The acousto-optic modulator is disposed in the optical path of the tunable incident laser light, and the radio frequency switch is connected to the acousto-optic modulator; the opening and closing of the radio frequency switch respectively control whether the acousto-optic modulator directs the tunable incident laser light towards the lens group to be measured; The MCU control is respectively connected to the AD sampling module and the radio frequency switch and is configured to, when the laser transmission power is the strongest, control the radio frequency switch to close.

7. The fineness test system for a high reflectivity lens according to claim 1, characterized in that The system further includes: an optical power detection module; The optical power detection module includes: an optical circulator and an optical power meter; The optical circulator is disposed in the optical path of the tunable incident laser light and is configured to receive the reflected light of the lens and direct the reflected light to the optical power meter; The optical power meter is connected to the optical circulator and is configured to receive the reflected light and determine the reflection power corresponding to the reflected light.

8. The fineness test system for a high reflectivity lens according to claim 1, characterized in that, The system further includes: a first mirror, a second mirror, and a third mirror; The first mirror and the second mirror are sequentially arranged in the optical path of the tunable incident laser, and are used to direct the tunable incident laser to the lens group to be measured through cooperation; The third mirror is arranged in the optical path of the transmitted laser, and is used to direct the transmitted laser to the optical detection module.

9. The fineness test system for a high reflectivity lens according to claim 1, characterized in that, The system further includes: a first lens; The first lens is arranged in the optical path of the transmitted laser, and is used to converge the transmitted laser to the test module.

10. A testing method for a fineness testing system of a high reflectivity lens, characterized in that, The system includes a light generation module, an optical detection module, a control module, and a test module; the method includes: Configuring the light generation module, the optical detection module, the control module, and the test module, so that the light generation module can generate tunable incident laser and emit it to the lens group to be measured; the lens group to be measured includes a pair of lenses with high-reflection surfaces facing inward; the frequency change range of the tunable incident laser covers the free spectral range of the lens group to be measured; Determining the output voltage and the laser transmission power of the transmitted laser generated by the tunable incident laser passing through the lens group to be measured; When the laser transmission power is the strongest, controlling the light generation module not to emit the tunable incident laser, and using the test module to determine the decay time corresponding to the output voltage; Determining the fineness of the lens based on the decay time.

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