CN1804572B - A method for measuring the reflectivity of high mirrors - Google Patents

Abstract

Translated fromChinese

一种高反镜反射率的测量方法，其特征在于：采用方波或正弦波调制的宽谱连续激光作光源，入射到两块高反镜组成的稳定谐振腔，由方波调制时单个周期波形的上升阶段和下降阶段拟合得到衰荡时间和腔镜反射率，或以锁相方式探测光腔输出信号的一次或奇次谐波，由其振幅和相位正切值随调制角频率的变化曲线拟合得到衰荡时间和腔镜反射率。保持腔长不变，加入测试镜组成稳定折叠腔，重复上述过程可得测试镜反射率。本发明测量精度高，成本低。

A method for measuring the reflectivity of a high mirror, characterized in that: a wide-spectrum continuous laser modulated by a square wave or a sine wave is used as a light source, incident to a stable resonant cavity composed of two high mirrors, and a single cycle is modulated by a square wave Fit the rising and falling stages of the waveform to obtain the ring-down time and the reflectivity of the cavity mirror, or detect the first or odd harmonic of the output signal of the optical cavity in a phase-locked manner, from the change of its amplitude and phase tangent with the modulation angular frequency The ring-down time and reflectivity of the cavity mirror are obtained by curve fitting. Keeping the cavity length constant, add a test mirror to form a stable folding cavity, and repeat the above process to obtain the reflectivity of the test mirror. The invention has high measurement precision and low cost.

Description

Translated fromChinese

一种高反镜反射率的测量方法A method for measuring the reflectivity of high mirrors

技术领域technical field

本发明涉及一种对光学元件参数的测量方法，特别一种高反镜反射率的测量方法。The invention relates to a method for measuring the parameters of an optical element, in particular to a method for measuring the reflectivity of a high mirror.

背景技术Background technique

随着激光功率不断提高，高功率激光系统对光学谐振腔腔镜的反射率的要求越来越高；随着镀膜技术的发展，镀膜工艺水平不断得到提高，能镀制高反镜的反射率也越来越高，已超过99.9％。为了准确评价激光器的腔镜参数和优化高反镜的镀制工艺，必须精确测量高反镜的反射率。With the continuous improvement of laser power, high-power laser systems have higher and higher requirements for the reflectivity of optical cavity mirrors; with the development of coating technology, the level of coating technology has been continuously improved, and the reflectivity of high mirrors can be coated. It is also getting higher and higher, exceeding 99.9%. In order to accurately evaluate the cavity mirror parameters of the laser and optimize the coating process of the high reflection mirror, it is necessary to accurately measure the reflectivity of the high reflection mirror.

测量反射率的传统方法，如分光光度计、白光池等方法，均以测量光强的比值为基础，误差大，最多只能给出三位有效数字。当反射率高于99.9％时，这些以光强比值测量为基础的方法通常都不能给出非常准确的反射率结果，无法满足对高反镜反射率测量精度的要求。“一种反射镜高反射率的测量方法”(中国专利申请号98114152.8，公开号CN1242516A，公开日期2000年1月26日)及“用光腔衰荡光谱方法精确测量高反镜的反射率”(中国激光，孙福革等，第26卷第1期35-38页，1999年1月)提供了一种高反射率测量方法，采用脉冲激光系统作光源，入射到两块高反镜组成的直型光学谐振腔，接收光腔指数衰减信号，确定直腔衰荡时间τ_-，然后保持腔长不变，加入待测镜组成折叠腔，确定折叠腔衰荡时间τ_＜，由两种情况的差值得到待测镜的反射率R。该方法采用折叠腔和直腔结合的方式，减小了由于腔内气体吸收、散射和衍射等损耗引起的测量误差，但该方法的测量精度受脉冲激光光束质量差、激光腔内模式竞争等因素的限制，而且由于使用的脉冲激光系统，造价在100万元人民币以上，不便于推广使用。The traditional methods of measuring reflectance, such as spectrophotometer, white light pool, etc., are based on the ratio of measured light intensity, and the error is large, and only three significant figures can be given at most. When the reflectivity is higher than 99.9%, these methods based on light intensity ratio measurement usually cannot give very accurate reflectivity results, and cannot meet the requirements for the measurement accuracy of high mirror reflectivity. "A method for measuring high reflectivity of mirrors" (Chinese Patent Application No. 98114152.8, Publication No. CN1242516A, publication date January 26, 2000) and "Using Optical Cavity Ring-Down Spectroscopy to Accurately Measure the Reflectivity of High Mirrors" (China Laser, Sun Fuge, etc., Vol. 26, No. 1, pp. 35-38, January 1999) provided a high reflectance measurement method, using a pulsed laser system as a light source, incident on a straight reflector composed of two high reflective mirrors. type optical resonant cavity, receive the exponentially attenuated signal of the optical cavity, determine the ring-down time τ_- of the straight cavity, then keep the cavity length constant, add the mirror to be tested to form a folded cavity, and determine the folded cavity ring-down time τ_< , by the two cases The difference is the reflectivity R of the mirror to be tested. This method uses the combination of folded cavity and straight cavity to reduce the measurement error caused by gas absorption, scattering and diffraction losses in the cavity. Due to the limitation of factors, and because of the pulse laser system used, the cost is more than 1 million yuan, which is not easy to promote and use.

发明内容Contents of the invention

本发明的目的在于避免采用脉冲激光系统作为光源的不足而提供一种以宽谱连续半导体激光器或其他连续激光器作为光源的高反镜反射率测量方法。The object of the present invention is to avoid the disadvantage of using pulsed laser system as light source and provide a high mirror reflectance measurement method using wide-spectrum continuous semiconductor laser or other continuous lasers as light source.

本发明的目的是通过以下措施达到的：一种高反镜反射率的测量方法，其特点在于：The object of the present invention is achieved by the following measures: a kind of measuring method of high mirror reflectivity is characterized in that:

(1)将一束方波或正弦波调制的宽谱连续激光，入射到两块平凹高反镜组成的稳定光学谐振腔；或两块平凹高反镜加一块平面测试镜组成的稳定折叠腔，两块平凹高反镜垂直于光路、凹面相对且使激光从镜面中心通过，保持腔长不变的情况下加入测试镜，使光路折叠成测试镜待测角度；激光从一平凹高反镜进入谐振腔或经过测试镜进行折叠腔，在谐振腔或折叠腔内来回多次反射，部分激光束从另一平凹高反镜输出，由光电探测器(光电二极管探测器或光电倍增管)接收该输出激光束得到输出电流或电压信号；(1) A wide-spectrum continuous laser beam modulated by a square wave or a sine wave is incident on a stable optical resonator composed of two flat-concave high-reflection mirrors; or a stable optical resonator composed of two flat-concave high-reflection Folding cavity, two flat-concave high-reflection mirrors are perpendicular to the optical path, the concave surfaces are opposite and the laser passes through the center of the mirror, and a test mirror is added while keeping the cavity length constant, so that the optical path is folded into the angle of the test mirror; the laser passes through a flat-concave The high reflective mirror enters the resonant cavity or folds the cavity through the test mirror, and reflects back and forth multiple times in the resonant cavity or folded cavity, and part of the laser beam is output from another flat and concave high reflective mirror, which is detected by the photodetector (photodiode detector or photomultiplier) tube) receiving the output laser beam to obtain an output current or voltage signal;

(2)记录输出电流或电压信号的波形、一次或奇次谐波振幅和相位，从而得到衰荡时间、腔镜和测试镜的反射率。采用数字示波器记录电流或电压信号的波形，用锁相放大器记录该信号波形的一次或奇次谐波的振幅和相位，通过理论拟合输出信号波形、或者拟合信号波形的一次或奇次谐波的振幅和相位的频率变化曲线均可得到衰荡时间，从而得到衰荡时间、腔镜和测试镜的反射率。(2) Record the waveform, first or odd harmonic amplitude and phase of the output current or voltage signal, so as to obtain the ring-down time, the reflectivity of the cavity mirror and the test mirror. Use a digital oscilloscope to record the waveform of the current or voltage signal, use a lock-in amplifier to record the amplitude and phase of the first or odd harmonic of the signal waveform, and theoretically fit the output signal waveform, or fit the first or odd harmonic of the signal waveform The frequency variation curve of the amplitude and phase of the wave can be used to obtain the ring-down time, thereby obtaining the ring-down time, the reflectivity of the cavity mirror and the test mirror.

所述的宽谱连续调制激光采用连续半导体激光器或二极管泵浦的固体激光器或光纤激光器或气体激光器作为光源，谱宽0.001nm至50nm，波长0.2至11μm。The wide-spectrum continuously modulated laser uses a continuous semiconductor laser or a diode-pumped solid-state laser or a fiber laser or a gas laser as a light source, with a spectral width of 0.001 nm to 50 nm and a wavelength of 0.2 to 11 μm.

所述步骤(2)中的衰荡时间、腔镜和测试镜的反射率由输出信号振幅随调制角频率的变化曲线拟合得到。The ring-down time in the step (2), the reflectivity of the cavity mirror and the test mirror are obtained by fitting the output signal amplitude with the variation curve of the modulation angular frequency.

所述步骤(2)中的衰荡时间、腔镜和测试镜的反射率由输出信号相位正切值随调制角频率的变化曲线拟合得到，或者由单一调制角频率处光腔输出信号一次或奇次谐波的相位直接得到。The ring-down time in the step (2), the reflectivity of the cavity mirror and the test mirror are obtained by fitting the output signal phase tangent value with the variation curve of the modulation angular frequency, or the output signal of the optical cavity at a single modulation angular frequency once or The phases of the odd harmonics are obtained directly.

所述步骤(2)中的衰荡时间、腔镜和测试镜的反射率由方波调制时单个周期输出信号波形的上升阶段和下降阶段拟合得到。The ring-down time in the step (2), the reflectivity of the cavity mirror and the test mirror are obtained by fitting the rising phase and the falling phase of the output signal waveform of a single period during square wave modulation.

本发明的原理是：采用连续半导体激光器或二极管泵浦的固体激光器或气体激光器作光源，要求谱宽在0.001nm至50nm之间，使激光频谱内有几个至几万个纵模与光腔本征频率共振，确保始终有激光能量耦合进光腔；以方波或正弦波调制激光，入射到两块腔镜组成的稳定光学谐振腔，或两块腔镜加一块测试镜组成的稳定折叠腔，并在腔内来回反射，采用锁相技术记录输出信号一次谐波或奇次谐波的振幅和相位，由振幅和相位直接得到衰荡时间、腔镜和测试镜的反射率，或者由不同调制角频率下的振幅和相位正切值拟合得到衰荡时间、腔镜和测试镜的反射率，或者由方波调制时单个输出信号周期波形的上升阶段和下降阶段拟合得到衰荡时间、腔镜和测试镜的反射率。The principle of the present invention is: using a continuous semiconductor laser or a diode-pumped solid-state laser or a gas laser as a light source, the spectral width is required to be between 0.001nm and 50nm, so that there are several to tens of thousands of longitudinal modes and optical cavities in the laser spectrum. The intrinsic frequency resonance ensures that laser energy is always coupled into the optical cavity; the laser is modulated with a square wave or a sine wave, and is incident on a stable optical resonator composed of two cavity mirrors, or a stable folding composed of two cavity mirrors and a test mirror The cavity, and reflect back and forth in the cavity, use the phase-locking technology to record the amplitude and phase of the first harmonic or odd harmonic of the output signal, and directly obtain the ring-down time, the reflectivity of the cavity mirror and the test mirror from the amplitude and phase, or by The amplitude and phase tangent values at different modulation angular frequencies are fitted to obtain the ring-down time, the reflectivity of the cavity mirror and the test mirror, or the ring-down time is obtained by fitting the rising phase and falling phase of a single output signal cycle waveform when modulated by a square wave , Reflectivity of cavity mirror and test mirror.

本发明与现有技术相比具有如下优点：Compared with the prior art, the present invention has the following advantages:

1.测量精度高。相对于脉冲激光器，半导体激光器或二极管泵浦的固体激光器或气体激光器输出功率稳定，光束质量高，有利于提高测量精度。由于单个频率下的相位能直接计算出衰荡时间和反射率，本发明中的拟合方法实质上是一种平均，有利于提高测量精度。1. High measurement accuracy. Compared with pulsed lasers, semiconductor lasers or diode-pumped solid-state lasers or gas lasers have stable output power and high beam quality, which is conducive to improving measurement accuracy. Since the ring-down time and reflectivity can be directly calculated from the phase at a single frequency, the fitting method in the present invention is essentially an average, which is beneficial to improving measurement accuracy.

2.装置简单，造价低。采用半导体激光器或其他连续激光器作为光源，避免了复杂、昂贵的脉冲激光系统。2. The device is simple and the cost is low. Using semiconductor lasers or other continuous lasers as light sources avoids complex and expensive pulsed laser systems.

3.可测任意波段高反镜的反射率。由于目前半导体激光器已可覆盖紫外、可见至红外波段，本方法适用于几乎所有波段高反镜反射率的测量。3. It can measure the reflectivity of high reflection mirrors in any wavelength band. Since the current semiconductor lasers can cover the ultraviolet, visible to infrared bands, this method is suitable for the measurement of high mirror reflectivity in almost all bands.

4.可靠性高。由于采用多种方式确定高反镜的反射率，可提高测量结果的可靠性。4. High reliability. The reliability of the measurement results is increased due to the multiple ways of determining the reflectivity of highly reflective mirrors.

附图说明Description of drawings

图1为本发明的直腔测量装置结构示意图；Fig. 1 is the structural representation of straight chamber measuring device of the present invention;

图2为本发明的测试镜角度为45度时的折叠腔测量结构示意图；Fig. 2 is a schematic diagram of the measurement structure of the folding cavity when the angle of the test mirror of the present invention is 45 degrees;

图3为本发明的腔长60cm、100kHz方波调制时波形上升阶段拟合结果；Fig. 3 is the fitting result of the rising stage of the waveform when the cavity length of the present invention is 60cm and 100kHz square wave modulation;

图4为本发明的腔长60cm、100kHz方波调制时波形下降阶段拟合结果；Fig. 4 is the fitting result of the waveform descending stage when the cavity length of the present invention is 60cm and 100kHz square wave modulation;

图5为本发明的腔长80cm时一次谐波振幅随调制角频率变化的曲线拟合结果；Fig. 5 is the curve fitting result that the first harmonic amplitude varies with the modulation angular frequency when the cavity length of the present invention is 80cm;

图6为本发明的腔长80cm时一次谐波相位正切值随调制角频率变化的曲线拟合结果。Fig. 6 is the curve fitting result of the first harmonic phase tangent value changing with the modulation angular frequency when the cavity length of the present invention is 80 cm.

具体实施方式Detailed ways

如图1所示，本发明的测量装置由光源1、反射镜2、望远系统3、双色分光镜4、氦氖激光器5、腔镜6、探测器7、函数发生器8、锁相放大器9和数字示波器10组成，函数发生器8连接至光源1使光源方波调制，同时连接至锁相放大器9作为参考信号和数字示波器10作为同步触发信号。探测器6输出的信号同时连接到锁相放大器9和数字示波器10，以记录振幅和相位以及光腔输出波形。如图2所示，加入45度待测镜11组成稳定折叠腔，可测量任意高反镜的反射率。As shown in Figure 1, measuring device of the present invention is made oflight source 1,reflector 2,telescopic system 3, dichroic beam splitter 4, helium-neon laser 5,cavity mirror 6,detector 7,function generator 8, lock-inamplifier 9 and adigital oscilloscope 10. Thefunction generator 8 is connected to thelight source 1 to modulate the light source with a square wave. It is also connected to the lock-inamplifier 9 as a reference signal and thedigital oscilloscope 10 as a synchronous trigger signal. The signal output by thedetector 6 is simultaneously connected to a lock-inamplifier 9 and adigital oscilloscope 10 to record the amplitude and phase as well as the output waveform of the optical cavity. As shown in Figure 2, a 45-degree mirror 11 to be tested is added to form a stable folding cavity, which can measure the reflectivity of any high mirror.

光源1采用可调制的半导体激光器，其中心波长828nm，谱宽0.03nm，TEM00模输出，功率106mW，Melles Griot，由函数发生器8采用DS335，调制范围1μHz～3.1MHz，Stanford Research Systems)方波调制；反射镜2使光路偏转并便于调节输出激光的方向，望远系统3使激光模式与衰荡腔的本征横模相匹配，双色分光镜使828nm激光透射、632.8nm激光全反射，主要作用在于引入氦氖激光辅助调节光路。氦氖激光器5(输出功率5mW，Melles Griot)辅助调节光路。两块相同的平凹高反镜6，其反射带中心波长828nm，曲率半径1m组成稳定的衰荡光腔，衰荡腔输出激光束由硅光电探测器7(PDA55，Thorlabs)接收。硅光电探测器输出的电信号波形由数字示波器10(Tektronix TDS5054B)记录。硅光电探测器输出的电信号一次谐波的振幅和相位由锁相放大器(频率范围0.5Hz-2.0MHz，Signal Recovery7280)记录，参考信号由函数发生器8提供。实验中，通过调节函数发生器的频率改变方波调制信号频率。调制频率f范围取1kHz～1MHz，调制角频率为2πf。数据处理中需要扣除系统响应的影响，测量系统响应的具体做法：光路中，只放一块腔镜，记录对应调制角频率下的相位。Light source 1 is a modulated semiconductor laser with a central wavelength of 828nm and a spectral width of 0.03nm, TEM00 mode output, power 106mW, Melles Griot,function generator 8 using DS335, modulation range 1μHz-3.1MHz, Stanford Research Systems) square wave Modulation; themirror 2 deflects the optical path and facilitates the adjustment of the direction of the output laser. Thetelescopic system 3 matches the laser mode with the intrinsic transverse mode of the ring-down cavity. The function is to introduce helium-neon laser to assist in adjusting the optical path. He-Ne laser 5 (output power 5mW, Melles Griot) assists in adjusting the optical path. Two identical flat-concave high-reflection mirrors 6 have a center wavelength of 828nm in the reflection band and a radius of curvature of 1m to form a stable ring-down optical cavity. The laser beam output from the ring-down cavity is received by a silicon photodetector 7 (PDA55, Thorlabs). The electrical signal waveform output by the silicon photodetector was recorded by a digital oscilloscope 10 (Tektronix TDS5054B). The amplitude and phase of the first harmonic of the electrical signal output by the silicon photodetector are recorded by a lock-in amplifier (frequency range 0.5Hz-2.0MHz, Signal Recovery7280), and the reference signal is provided by afunction generator 8. In the experiment, the frequency of the square wave modulation signal is changed by adjusting the frequency of the function generator. The range of modulation frequency f is 1kHz-1MHz, and the modulation angular frequency is 2πf. In the data processing, the influence of the system response needs to be deducted, and the specific method of measuring the system response: put only one cavity mirror in the optical path, and record the phase at the corresponding modulation angular frequency.

如图3为腔长60cm、100kHz方波调制时时波形上升阶段曲线拟合结果，得到衰荡时间0.692μs、腔镜反射率99.711％。图4为腔长60cm、100kHz方波调制时时波形下降阶段曲线拟合结果，得到衰荡时间0.706μs、腔镜反射率99.717％。As shown in Figure 3, the curve fitting results of the rising phase of the waveform with a cavity length of 60cm and 100kHz square wave modulation are obtained. The ring down time is 0.692μs and the reflectivity of the cavity mirror is 99.711%. Fig. 4 shows the curve fitting results of the waveform descending stage when the cavity length is 60cm and the square wave modulation is 100kHz, and the ring-down time is 0.706μs and the reflectivity of the cavity mirror is 99.717%.

图5为腔长80cm时振幅随调制角频率变化的曲线拟合结果，得到衰荡时间0.975μs、腔镜反射率99.726％。图6为腔长80cm时相位正切值随调制角频率变化的曲线拟合结果，得到衰荡时间0.940μs、腔镜反射率99.716％。Fig. 5 is the curve fitting result of the amplitude changing with the modulation angular frequency when the cavity length is 80cm, and the ring-down time is 0.975μs and the reflectivity of the cavity mirror is 99.726%. Figure 6 shows the curve fitting results of the phase tangent value changing with the modulation angular frequency when the cavity length is 80cm, and the ring-down time is 0.940μs and the reflectivity of the cavity mirror is 99.716%.

Claims (5)

Translated fromChinese

1.一种高反镜反射率的测量方法，其特征在于：1. A measuring method of high mirror reflectivity, characterized in that:(1)将一束方波或正弦波调制的宽谱连续激光，入射到两块平凹高反镜组成的稳定光学谐振腔；两块平凹高反镜垂直于光路、凹面相对且使激光从镜面中心通过；激光从一平凹高反镜进入光学谐振腔，在谐振腔内来回多次反射，部分激光束从另一平凹高反镜输出，由光电探测器接收该输出激光束得到光学谐振腔的输出电流或电压信号，即光学谐振腔输出信号；(1) A wide-spectrum continuous laser beam modulated by a square wave or a sine wave is incident into a stable optical resonant cavity composed of two flat-concave high-reflection mirrors; Pass through the center of the mirror; the laser enters the optical resonant cavity from a flat-concave high-reflection mirror, and is reflected back and forth multiple times in the resonator, and part of the laser beam is output from another flat-concave high-reflection mirror, and the output laser beam is received by the photodetector to obtain optical resonance The output current or voltage signal of the cavity, that is, the output signal of the optical resonant cavity;(2)保持腔长不变，在所述光学谐振腔中加入测试镜，使光路折叠成测试镜待测角度，构成由两块高反镜和一块测试镜组成的稳定折叠腔；激光从一平凹高反镜进入折叠腔，在折叠腔内来回多次反射，部分激光束从另一平凹高反镜输出，由光电探测器接收该输出激光束得到折叠腔的输出电流或电压信号，即折叠腔输出信号；(2) Keeping the length of the cavity constant, add a test mirror in the optical resonant cavity, so that the optical path is folded into the angle of the test mirror to be measured, forming a stable folding cavity composed of two high reflection mirrors and a test mirror; The concave high mirror enters the folding cavity and reflects back and forth multiple times in the folding cavity. Part of the laser beam is output from another flat concave high mirror, and the output laser beam is received by the photodetector to obtain the output current or voltage signal of the folding cavity, that is, the folding Cavity output signal;(3)记录光学谐振腔输出信号和折叠腔输出信号的波形，或光学谐振腔输出信号和折叠腔输出信号基波或奇次谐波振幅和相位，从而分别得到光学谐振腔衰荡时间、高反镜反射率和折叠腔衰荡时间、测试镜反射率；采用数字示波器记录光学谐振腔输出信号和折叠腔输出信号的波形，用锁相放大器记录光学谐振腔输出信号和折叠腔输出信号基波或奇次谐波的振幅和相位；通过拟合光学谐振腔输出信号和折叠腔输出信号波形得到光学谐振腔衰荡时间和折叠腔衰荡时间，或者通过拟合光学谐振腔输出信号和折叠腔输出信号基波或奇次谐波的振幅随调制角频率的变化曲线得到光学谐振腔衰荡时间和折叠腔衰荡时间，或者通过拟合光学谐振腔输出信号和折叠腔输出信号基波或奇次谐波的相位正切值随调制角频率的变化曲线得到光学谐振腔衰荡时间和折叠腔衰荡时间，或者由单一调制角频率处光学谐振腔输出信号和折叠腔输出信号基波或奇次谐波的相位直接得到光学谐振腔衰荡时间和折叠腔衰荡时间，从而得到高反镜反射率和测试镜的反射率。(3) Record the waveforms of the output signal of the optical resonant cavity and the output signal of the folded cavity, or the amplitude and phase of the fundamental or odd harmonics of the output signal of the optical resonant cavity and the output signal of the folded cavity, so as to obtain the ring-down time of the optical resonant cavity, high Mirror reflectivity and folded cavity ring down time, test mirror reflectivity; use digital oscilloscope to record the output signal of optical resonant cavity and waveform of folded cavity output signal, use lock-in amplifier to record the output signal of optical resonant cavity and the fundamental wave of output signal of folded cavity Or the amplitude and phase of the odd harmonic; by fitting the output signal of the optical resonator and the output signal waveform of the folded cavity, the ring-down time of the optical resonator and the ring-down time of the folded cavity are obtained, or by fitting the output signal of the optical resonator and the folded cavity The amplitude of the fundamental wave or odd harmonic of the output signal varies with the modulation angular frequency to obtain the ring-down time of the optical resonator and the ring-down time of the folded cavity, or by fitting the output signal of the optical resonator and the output signal of the folded cavity The change curve of the phase tangent value of the subharmonic with the modulation angular frequency can be used to obtain the ring-down time of the optical resonator and the ring-down time of the folded cavity, or the fundamental wave or odd order of the output signal of the optical resonator and the output signal of the folded cavity at a single modulation angular frequency The phase of the harmonic directly obtains the ring-down time of the optical resonant cavity and the ring-down time of the folded cavity, thereby obtaining the reflectivity of the high mirror and the reflectivity of the test mirror.2.根据权利要求1所述的高反镜反射率的测量方法，其特征在于：所述的宽谱连续激光采用连续半导体激光器或二极管泵浦的固体激光器或光纤激光器或气体激光器作为光源，谱宽0.001nm至50nm，波长0.2至11μm。2. the measuring method of high mirror reflectivity according to claim 1, is characterized in that: described wide-spectrum continuous laser adopts continuous semiconductor laser or diode-pumped solid laser or fiber laser or gas laser as light source, spectrum Width 0.001nm to 50nm, wavelength 0.2 to 11μm.3.根据权利要求1所述的高反镜反射率的测量方法，其特征在于：所述的宽谱连续激光的调制采用方波或者正弦波调制激光驱动电源，或者采用声光调制器调制激光束。3. the measuring method of high mirror reflectivity according to claim 1, is characterized in that: the modulation of described wide-spectrum continuous laser adopts square wave or sine wave to modulate laser drive power supply, or adopts acousto-optic modulator to modulate laser bundle.4.根据权利要求1所述的高反镜反射率的测量方法，其特征在于：所述的步骤(3)中的光学谐振腔衰荡时间和高反镜反射率由方波调制时单个周期内光学谐振腔输出信号波形的上升阶段和下降阶段拟合得到；折叠腔衰荡时间和测试镜反射率由方波调制时单个周期内折叠腔输出信号波形的上升阶段和下降阶段拟合得到。4. the method for measuring of high mirror reflectivity according to claim 1, is characterized in that: optical resonant cavity ring-down time in described step (3) and high mirror reflectivity are by square wave modulation single period The rising stage and falling stage of the output signal waveform of the inner optical resonant cavity are fitted; the ring-down time of the folded cavity and the reflectivity of the test mirror are obtained by fitting the rising stage and falling stage of the output signal waveform of the folded cavity in a single period of square wave modulation.5.根据权利要求1所述的高反镜反射率的测量方法，其特征在于：所述的测试镜待测角度为5-75度。5. The measuring method of high mirror reflectivity according to claim 1, characterized in that: the angle to be measured of the test mirror is 5-75 degrees.

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