Influence of cavity ring-down data interception on time constant measurement accuracy
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摘要: 光腔衰荡方法是目前测量光学元件超高反射率(反射率>99.9%)的唯一方法。介绍了一种对光腔衰荡法中激光信号强度与时间关系的优化提取方法。设计了基于光腔衰荡法的光学元件超高反射比的测试系统,通过对采集的光腔衰荡曲线数据进行分段指数拟合,将光腔衰荡曲线数据分为5段,对每段指数拟合结果对应的R2 (R-square)和RMSE(root mean squared error)值进行对比分析,计算每段指数拟合的衰荡时间。实验结果表明:截取光腔衰荡曲线数据40%~60%部分拟合得到的结果最接近真实值,求得对应的腔镜的反射率为99.988 977%。最后通过与腔镜的自身反射率进行比较,表明该种数据拟合方法能有效地测量腔镜的反射率,并能减小实验数据本身带来的误差。Abstract: The cavity ring-down method is currently the only method for measuring ultra-high reflectivity (reflectivity is greater than 99.9%) of optical elements. An optimal extraction method for the relationship between laser signal intensity and time in cavity ring-down method was introduced, and a test system for ultra-high reflection ratio of optical elements based on cavity ring-down method was designed. The data of cavity ring-down curve were divided into five sections by piecewise exponential fitting, the R2 (R-square) and root-mean-square error (RMSE) values corresponding to the index fitting results of each section were compared and analyzed, and the ring-down time of each index fitting was calculated. The experimental results show that the results obtained from 40%~60% of the cavity ring-down curve data are closest to the real value, and the reflectivity of the corresponding cavity mirror is 99.988 977%. Finally, by comparing with the reflectance of the cavity mirror, it is shown that this data fitting method can effectively measure the reflectivity of the cavity mirror and reduce the error caused by the experimental data.
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表 1 6组实验数据的处理值
Table 1 Processing values of six groups of experimental data
试验组数 第3组 第8组 第13组 第18组 第23组 第28组 ${ {R} }^{2}$ 0.994 6 0.994 3 0.994 2 0.994 1 0.994 3 0.994 3 $ {\rm{RMSE}} $ 4.922 4.952 4.913 4.950 4.820 4.851 表 2 第23组指数函数拟合统计值
Table 2 Fitting statistics of exponential function of group 23
拟合函数次数 一次指数拟合 二次指数拟合 ${ {R} }^{2}$ 0.994 3 0.999 0 $ {\rm{RMSE}} $ 4.820 1.999 表 3 5段数据求得的参数值
Table 3 Parameter values obtained from five segments of data
数据 1~500 501~1 000 1 001~1 500 1 501~2 000 2 001~2 500 $\tau $ 16.949 15 19.801 98 30.238 887 70.821 53 228.519 56 $R$ 0.999 803 0.999 831 7 0.999 889 77 0.999 952 9 0.999 985 4 ${ {R} }^{2}$ 0.994 8 0.980 9 0.906 8 0.633 1 0.164 5 $ {\rm{RMSE}} $ 4.812 2.021 1.059 0.609 2 0.444 6 -
[1] SANDERS V. High-precision reflectivity measurement technique for low-loss laser mirrors[J]. Applied Optics,1997,16(1):19-20. [2] ANDERSON D Z, FRISCH J C, MASSER C S. Mirror reflectometer based on optical cavity decay time[J]. Applied Optics,1984,23(8):1238-1245. doi: 10.1364/AO.23.001238 [3] OKEEFE A, DEACON D A G. Cavity ring-down optical spectrometer for absorption measurements using pulsed laser sources[J]. Review of Scientific Instruments,1988,59(12):2544-2551. doi: 10.1063/1.1139895 [4] MANNE J O, SUKHORCUKOV W T, TULIP T. Pulsed quantym cascade laser-based cavity ring-down spectroscopy for ammonia detection in breath[J]. Appl. Opt.,2006,45(36):9230-9237. doi: 10.1364/AO.45.009230 [5] 李斌成, 龚元. 光腔衰荡高反射率测量技术综述[J]. 激光与光电子学进展,2010,47(2):1-11.LI Bincheng, GONG Yuan. Review of cavity ring-down technique for high reflectivity measurements[J]. Lasser & Optoelectronics Progress,2010,47(2):1-11. [6] HAYDEN J, WESTBERG J, PATRICK C B, et al. Frequency-locked cavity ring-down faraday rotation spectroscopy[J]. Opt. Lett.,2018,43:5046-5049. doi: 10.1364/OL.43.005046 [7] 崔浩, 李斌成, 肖石磊, 等. 光反馈光腔衰荡技术同时测量高反膜S和P偏振反射率[J]. 电子科技大学学报,2018,47(2):307-310. doi: 10.3969/j.issn.1001-0548.2018.02.024CUI Hao, LI Bincheng, XIAO Shilei, et al. Simultaneous measurement of S-and P-polarization reflectivity using optical feedback cavity ring down technique[J]. Journal of University of Electronic Science and Technology of China,2018,47(2):307-310. doi: 10.3969/j.issn.1001-0548.2018.02.024 [8] 易亨瑜, 彭勇, 胡晓阳, 等. 衰荡腔腔长失调的实验分析[J]. 中国激光,2004,31(增刊I):486-488. doi: 10.3321/j.issn:0258-7025.2004.z1.162YI Hengyu, PENG Yong, HU Xiaoyang, et al. Experimental analysis of length misalignment of ring-down cavity[J]. Chinese Journal of Lasers,2004,31(SI):486-488. doi: 10.3321/j.issn:0258-7025.2004.z1.162 [9] 高丽峰, 熊胜强, 李斌成, 等. 用光腔衰荡技术测量镜片的反射率[J]. 强激光与粒子束, 2005, 17(3): 335-338.GAO Lifeng, XIONG Shengqiang, LI Bincheng, et al. Optical cavity ring-down technique for reflectance measurement of optical lens [J]. High Power Laser and Particle Beams, 2005, 17(3): 335-338. [10] 易亨瑜, 齐予, 张凯. 超高反射率测量研究[J]. 应用光学,2020,41(sup):52-58.YI Hengyu, QI Yu, ZHANG Kai. Measurement of ultra-high reflectivity[J]. Journal of Applied Optics,2020,41(sup):52-58. [11] 高爱华, 王少刚, 闫丽荣. 一种高精度激光吸收率测量装置[J]. 应用光学,2016,37(2):303-307. doi: 10.5768/JAO201637.0207001GAO Aihua, WANG Shaogang, YAN Lirong. A high precision laser absorptivity measurement device[J]. Journal of Applied Optics,2016,37(2):303-307. doi: 10.5768/JAO201637.0207001 [12] LEI Wei, CHEN Haiyan. Reflectivity measurement of fiber Bragg grating by cavity ring-down spectroscopy technique[J]. Optik, 2018, 172: 526-530. [13] KIVLCIM Y, ANIL Y. Nalysis of a novel sensor interrogation technique based on fiber cavity ring-down (CRD) loop and OTDR[J]. Optical Fiber Technology,2018,43:57-61. doi: 10.1016/j.yofte.2018.04.005 [14] LIU X, SHU X. Design of an all-optical fractional-order differentiator with terahertz bandwidth based on a fiber Bragg grating in transmission[J]. Appl. Opt.,2017,56:6714-6719. doi: 10.1364/AO.56.006714 [15] CHAOUI F, AGHZOUT O, ALEJOS A V, et al. Closed-form expression to optimize the fiber Bragg grating sensor apodization performance Microw[J]. Opt. Technol. Lett.,2017,59:1947-1950. doi: 10.1002/mop.30658 [16] 杨林华, 许杰, 蒋山平. 真空低温环境反射镜光谱反射率原位测量技术[J]. 应用光学,2015,36(4):559-565. doi: 10.5768/JAO201536.0403001YANG Linhua, XU Jie, JIANG Shanping. A high precision laser absorptivity measurement device[J]. Journal of Applied Optics,2015,36(4):559-565. doi: 10.5768/JAO201536.0403001 [17] 易亨瑜. 反射率测量中腔失调衰荡波形仿真[J]. 中国激光,2006,33(3):399-404. doi: 10.3321/j.issn:0258-7025.2006.03.024YI hengyu. simulation of cavity misalignment ring-down waveform in reflectivity measurement[J]. Chinese journal of lasers,2006,33(3):399-404. doi: 10.3321/j.issn:0258-7025.2006.03.024 [18] 易亨瑜, 胡晓阳, 陈门雪. 超高反射率测量系统的精密调试[J]. 红外与激光工程,2007,36(增刊I):258-260.YI Hengyu, HU Xiaoyang, CHEN Menxue. Precision debugging of ultra-high reflectivity measurement system[J]. Infrared and Laser Engineering,2007,36(SI):258-260. [19] LV R Q, ZHAO Y, LIU M C. Determination of refractive index by fiber-loop cavity ring-down spectroscopy and a long-period fiber grating Instrum[J]. Sci. Technol.,2016,44:547-557. [20] 王金舵, 余锦, 貊泽强, 等. 连续波腔衰荡光谱技术中模式筛选的数值方法[J]. 物理学报,2019,68(24):159-169.WANG Jintuo,YU Jin,BAI Zeqiang,et al. Numerical method for mode selection in CWcavity ring-down spctroscopy[J]. Journal of Physics,2019,68(24):159-169. [21] 杜星湖, 薛颖, 何星, 等. 基于耦合光腔衰荡技术的高反射率测量[J]. 中国激光,2020,47(6):222-226.DU Xinghu, XUE Ying,HE Xing,et al. High reflectance measurement based on coupled cavity ring-down technique[J]. Chinese Laser,2020,47(6):222-226. -