一种基于两块PEM调制器的光谱测量方法（英文）

发布时间：2018-05-02 11:19

本文选题：光谱测量 + 弹光调制　；参考：《光谱学与光谱分析》2017年09期

【摘要】：弹光调制干涉信号范围为百赫兹到数十吉赫兹之间,而由于探测器阵列无法对该等级频率实现有效响应,因此,该情况使弹光调制器在光谱成像工作中受到限制。为了解决该问题,发展了一种使用两块具有相近谐振频率的PEM,并基于该频率差进行光信号调制的方法。该方法将两个弹光调制器分别工作在数值略有差异的频率f_1和f_2上,被测光通过双弹光调制器实现差频调制,因此干涉信号中产生载有被测光的低频调制分量,低频调制频率是以δ_i(σ,t)=δ_(0i)(σ)sin(ωit)为基频的一系列倍频信号,该低频调制信号使用普通探测器即可实现探测,再将直流和高频信号滤波后,仅对调制信号后的低频成分进行对应的运算即可得到被测光谱。由于该频率差比所使用PEM的谐振频率低2至3个数量级,因此,该方法可使探测器获得更多的响应时间,而且由于该方法并不需要所使用的两块PEM具有严格一致的谐振频率和相同的光程差,降低了系统本身的设计难度。
[Abstract]:Elasto-optic modulation interference signals range from 100 hertz to dozens of gigahertz, but the detector array can not effectively respond to this level of frequency, so the Elasto-optic modulator is limited in spectral imaging. In order to solve this problem, a method of optical signal modulation based on the frequency difference is developed, which uses two PEM blocks with similar resonant frequencies. In this method, the two elastic-light modulators are operated on the slightly different frequencies fflesh _ 1 and f _ s _ 2, respectively, and the difference frequency modulation is realized by means of the dielastic light modulator, so that the interference signal produces a low-frequency modulation component containing the light measured. The low frequency modulation frequency is a series of octave signals based on the basic frequency of 未 s _ I (蟽 _ T _ n = 未 _ S _ O _ I _ I (蟽 _ s _ (sin (蠅 _ it). The low-frequency modulation signal can be detected by using a common detector, and then the DC and high frequency signals are filtered. The measured spectrum can be obtained only by the corresponding operation of the low frequency component of the modulated signal. Since the frequency difference is two to three orders of magnitude lower than the resonant frequency of the PEM used, the method can obtain more response time for the detector. Because the two PEM blocks used in this method do not need to have the same resonant frequency and the same optical path difference, the design difficulty of the system is reduced.
【作者单位】：中北大学信息与通信工程学院;中北大学山西省光电信息与仪器工程技术研究中心;中北大学理学院;
【基金】：Key Program for International S&T Cooperation Projects of China(2013DFR10150) National Natural Science Foundation of China(61505180) Young Science Foundation of Shanxi Province(2015021084)
【分类号】：O433.1;TN761

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