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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。 相似文献
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基于谐振腔失调灵敏度参量随腔长的变化关系,提出了一种衰荡腔,它是由共焦腔将腔长缩短为原来的0.73得到的稳定腔。根据光束传输规律和失调腔矩阵方法,以及光腔衰荡法测量原理和曲线拟合方法,建立了腔长、腔镜角度失调下光腔衰荡法的反射率测量模型。通过数值模拟,研究了这种稳定衰荡腔中,腔微小失调对反射率测量结果的影响,并与相同失调情况下共焦衰荡腔的测量结果进行了对比分析。结果表明,这种稳定腔用作衰荡腔,测量结果受腔镜角度失调影响较大,而受腔长失调影响小;其长度较短,便于工程应用;衍射损耗较小,测量精度高。 相似文献
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只考虑腔长失调因素下建立了反射率模拟测量的理论模型。根据高斯光束传输规律分析了腔长失调对衰荡腔模式耦合的影响,推导了腔长失调与谐振腔输出脉冲信号、衰荡信号与反射率之间的关系,模拟了腔长失调在±10mm范围内的光脉冲衰荡现象。结果表明:对于光敏面直径为0.2mm的高速探测器,为了保证10-6的测量精度,腔长的失调量应控制在±1mm之间。在光路调节中采用具有对数变换功能的示波器和动态范围较大的探测器,可以提高测量精度。 相似文献
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基于通讯波段的分布式反馈半导体激光器(DFB),搭建了一套光腔衰荡光谱仪(CRDS)。衰荡光腔由一对反射率高于99.997%的高反镜组成,衰荡腔长约为130 cm,空腔衰荡时间约为150 μs。当光谱平均次数达到1 000次时,光谱仪灵敏度(最小可探测吸收系数)达到5×10-12 cm-1。利用热隔绝的方式稳定衰荡腔长,并使用衰荡光腔自身作为光学标准具,来标定光谱的频率:利用反馈式光谱扫描程序步进改变激光器频率,使之与衰荡腔的纵模频率逐一匹配,从而实现所测得光谱的自动标定。通过测量一氧化碳分子在1.565 μm附近的吸收光谱,测定气体中一氧化碳的含量。将光谱测量结果和标准样品中的一氧化碳含量进行对比,对装置的定量精度进行了检验,表明其对一氧化碳的探测极限达4 ppbv。利用该装置对实际大气中一氧化碳的含量进行了实时监测。 相似文献
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在利用光反馈光腔衰荡技术测量大口径光学元件反射率及其均匀性分布时,需要对光学元件进行二维扫描测量,而在扫描过程中光学元件的倾斜失调将对测量结果造成影响.本文根据失调谐振腔光束传输增广矩阵,通过数值运算模拟了在对称共焦腔和一般稳定腔情况下,光反馈衰荡腔结构中由样品倾斜失调引起的输出腔镜上光斑中心位置变化以及对反射率测量的影响.仿真结果表明:对称共焦腔情况下,输出腔镜上奇数次光斑无漂移,偶数次光斑漂移量为固定值|在一般稳定腔情况下,输出腔镜上奇偶数次光斑均往复振荡漂移.分析表明,该系统对样品失调角度的敏感程度与样品在腔内的位置以及腔长有关,通过改变样品在腔内位置,选择适当腔长以及包络拟合法可以减小样品失调对测量结果的影响. 相似文献
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V. L. Kasyutich 《Applied physics. B, Lasers and optics》2009,96(1):141-148
Propagation of an elliptical Gaussian beam in a multiple-pass optical cell formed by two twisted cylindrical mirrors has been
described by means of complex curvature tensors. Using the ABCD tensor approach various light patterns were computed for the use in tunable laser absorption spectroscopy with a multiple-pass
optical cell. Light patterns with high beam-spot density can be also defined for a cavity formed by two twisted cylindrical
high-reflectivity mirrors. In order to achieve higher cavity output intensity, a high-reflectivity cylindrical mirror cavity
with at least one mirror that has a central transparent spot for laser beam injection has been described for applications
in non-resonant cavity enhanced absorption spectroscopy.
The author was with TDL Sensors Ltd., when the experimental part of this work was performed. 相似文献
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We report the accurate and precise measurement of nitric oxide (NO) in automotive exhaust gas by cavity ring-down spectroscopy
(CRDS) using a thermoelectrically cooled, pulsed quantum cascade laser (QCL) as a light source. A mid-infrared QCL with a
5.26 μm wavelength was used to detect fundamental vibrational transitions of NO. An effective optical path length of 2.1 km
was achieved in a 50 cm long cell using high-reflectivity mirrors. In combination with a particle filter and a membrane gas
dryer, stable and sensitive measurement of NO in exhaust gas was achieved for more than 30 minutes with a time resolution
of 1 s. The results of this work indicate that a laser based NO sensor can be used to measure NO in exhaust gas over a dynamic
range of three orders of magnitude. 相似文献
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为测量高能激光传输系统中大口径高反射率光学元件的反射率,设计了一种大口径光学元件二维扫描的精密测量系统。介绍了该系统的结构及其工作原理,分析了影响系统测量精度的因素,从理论上分析了扫描系统的系统误差对测量精度的影响,结果表明在垂直于光束传播方向上,水平偏差在0.29 mm时,测量误差在10-6量级;腔长的变化量较小时,可通过对衰荡腔腔镜的调节,实现对旋转轴偏差的补偿及对系统的精细调节。通过拟合处理光强与时间的数据得到对应的一次指数函数拟合曲线,并通过计算得到衰荡时间和反射率,经过对比分析可知,该误差分析方法能比较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。 相似文献
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Kaixin Chen Hongbo Zhang Daming Zhang Han Yang Maobin Yi 《Optics & Laser Technology》2002,34(6):449-452
External electro-optic sampling utilizing a poled polymer asymmetry Fabry–Perot cavity as electro-optic probe tip has been demonstrated. Electro-optical polymer spin coated on the high-reflectivity mirror (HRM) was corona poled. Thus, an asymmetric F–P cavity was formed based on the different reflectivity of the polymer and HRM and it converted the phase modulation that originates from electro-optic effect of the poled polymer to amplitude modulation, so only one laser beam is needed in this system. The principle of the sampling was analyzed by multiple reflection and index ellipsoid methods. A 1.2 GHz microwave signal propagating on coplanar waveguide transmission line was sampled, and the voltage sensitivity about
was obtained. 相似文献
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A very sensitive optomechanical sensor to detect femtometer-level displacements in the position of one of the cavity mirrors
in a Fabry–Pérot interferometer was constructed and characterized. We use a high-reflectivity coated, non-tilting out-of-plane
mode high-Q mechanical silicon oscillator as a rear mirror in the Fabry–Pérot interferometer. The benefit of our novel oscillator,
if compared to traditional torsional, flexural and many bulk acoustic mode oscillators, is that the action of weak forces
is observed to cause only pure linear translation of the moving mirror without any tilting or deformation of the mirror surface.
This non-tilting behavior allows, in principle, more precise optical mode stabilization, use of very short optical cavities
and studies of short-range interactions between parallel surfaces. The resonance frequency and Q value of the high-reflectivity
coated silicon oscillator are f0=27.5 kHz and Q=19000 at low pressure (p=0.1 mbar) and at room temperature. The finesse of the optical cavity is . The sensitivity of the displacement measurement is Δxmin=5 fm with a 1 Hz bandwidth. The prospects of reaching the standard quantum limit in an interferometric displacement measurement
using a macroscopic oscillator are discussed.
PACS 78.70.-g; 07.10.Cm; 07.60.Ly 相似文献
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The possibility of performing in proximity of the Earth experiments to test the predictions of general relativity for the trajectories of particles and photons in weak gravitational fields is studied. Three experiments are analyzed, all based on optical detection methods. The first experiment would allow to detect the tidal acceleration using a freely-falling Michelson interferometer. In a second experiment, based on laser-ranging methods, the relativistic correction to the classical gravity acceleration could be detected. Finally, the possibility of detecting light deflection induced by space curvature in an optical cavity with high-reflectivity mirrors is discussed. 相似文献
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T. Laurila I. S. Burns J. Hult J. H. Miller C. F. Kaminski 《Applied physics. B, Lasers and optics》2011,102(2):271-278
An efficient calibration method has been developed for broad-bandwidth cavity enhanced absorption spectroscopy. The calibration
is performed using phase shift cavity ring-down spectroscopy, which is conveniently implemented through use of an acousto-optic
tunable filter (AOTF). The AOTF permits a narrowband portion of the SC spectrum to be scanned over the full high-reflectivity
bandwidth of the cavity mirrors. After calibration the AOTF is switched off and broad-bandwidth CEAS can be performed with
the same light source without any loss of alignment to the set-up. We demonstrate the merits of the method by probing transitions
of oxygen molecules O2 and collisional pairs of oxygen molecules (O2)2 in the visible spectral range. 相似文献
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夜间大气NO3自由基的氧化能力相当于白天OH自由基,鉴于NO3自由基在大气反应过程中的关键作用,准确测量其浓度及研究其夜间大气化学过程具有重大意义。采用以二极管激光器为光源(中心波长为662nm,半高宽0.3nm),两块高反射率镜片(R≥99.998 5%)形成的腔体为光学共振腔,有效光程达到约20km的腔衰荡光谱系统(CRDS)对夜间大气NO3自由基进行测量,并且针对秋冬季交通繁忙区域夜间大气边界层NO3自由基化学过程进行研究。采用该系统于2014年10月29日—11月15日在北京市中国科学院大学校园开展了NO3自由基连续外场观测实验,观测期间NO3自由基浓度相对较低,最大浓度约为50pptv,平均值为10pptv。并结合NO2,NO和O3等相关辅助数据对测量结果进行分析,分析表明在观测期间NO3自由基产率为0.04~1.03pptv·s-1,平均寿命约为68s。并且近一步分析了观测期间大气NO3自由基损耗途径,探讨了不同湿度及颗粒物浓度对其损耗的影响。即观测期间当大气中RH≥60%,PM2.5浓度大部分大于60μg·m-3时,ln(τss(NO3))与ln(NO2)的相关性达到0.79,大气中NO3自由基损耗主要以间接为主;然而在RH≤40%,PM2.5浓度大部分小于60μg·m-3时,因测量点靠近国道受局地污染源影响,直接损耗较显著;当大气中40%RH60%时,直接损耗与间接损耗途径都存在且不可忽视。 相似文献
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Shuai Zhang Xiaofeng Duan Gongqing Li Kai Liu Yongqing Huang Xiaomin Ren 《Optical and Quantum Electronics》2018,50(8):320
We report a high-reflectivity non-periodic sub-wavelength gratings (SWGs) mirror with small-angle beam-steering ability for reflect light. It presents a distinctive characteristic of flexibly controlling the width of oscillation optical field for the improved Fabry–Perot (F–P) cavity. We propose a detailed principle analysis of the improved cavity. By finding out a set of SWGs with the designed structural parameters, both high reflectivity (>?93%) and beam steering (1°) can be implemented. By setting beam-steering angle and cavity length, we can control the width of oscillation optical field in the improved cavity. Beam steering ability and property of controlling the oscillation width are numerically investigated by finite element method. Simulation results prove that cavity length and steering angle can effectively control the main width of oscillation optical field, and the width is linearly associated with the cavity length. 相似文献
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K.X. Chen H. Yang H.B. Zhang Y. Zhao M.B. Yi 《Applied physics. B, Lasers and optics》2002,74(4-5):363-366
The sampling of high-frequency signals using poled electro-optic polymer films as electro-optic probe tips has been demonstrated
for the first time. The electro-optic polymer, which was spin coated onto a high-reflectivity glass substrate, was corona
poled; thus an asymmetric Fabry–Perot microcavity was formed, based on the difference between the polymer reflectivity and
that of high-reflectivity glass. This converts phase modulation to amplitude modulation, so only one laser beam is needed
in this system. The sampling technique has been analyzed by multiple reflection and index ellipsoid methods. A 1.2 GHz microwave
signal propagating on a coplanar waveguide transmission line has been sampled, and a voltage sensitivity of about 0.5 mV/ was obtained.
Received: 16 August 2001 / Revised version: 20 November 2001 / Published online: 14 March 2002 相似文献