光谱学与光谱分析, 2017, 37 (9): 2966, 网络出版: 2017-10-16  

一种基于两块PEM调制器的光谱测量方法

Spectral Measurements Based on Difference Frequency Modulation of Two PEMs Modulators
李世伟 1,2,*王召巴 1,2张瑞 1,2王志斌 1,2,3
作者单位
1 中北大学信息与通信工程学院, 山西 太原 030051
2 中北大学山西省光电信息与仪器工程技术研究中心, 山西 太原 030051
3 中北大学理学院, 山西 太原 030051
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f1和f2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δi(σ,t)=δ0i(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
Due to the fact that the photoelastic modulator (PEM) interference signal frequency ranges from hundreds of megahertz to several gigahertz, and the array detector can not be applied to such high responded frequency, the application of PEM in spectral imaging is greatly limited . To solve this problems, a method is proposed in this paper to produce two PEMs of slightly different resonant frequencies with f1 and f2 which are applied to modulate the inputting optical signal. This method operates two PEMs of slightly different resonant frequencies f1 and f2 respectively, and the incident light can be modulated by the frequency difference of two PEM system. Thus, the interference signal contains low frequency modulation components contains the information of the incident light, and low frequency modulation component consists of a series of frequency-multiplier signals whose fundamental frequency is (f1-f2)/2. This low frequency modulation components can be detected with normal detector. After filtering the direct current component and high frequency signal, the incident light spectra can be obtained by the corresponding calculation. Since the difference frequency can be 2~3 orders of magnitude lower than the original resonant frequency of PEM, it can offer more time to array detector to process the inputting signal. What’s more, it does not require the same path difference and resonant frequency for the two PEMs, which can reduce the difficulty to PEM modulator design and control.

李世伟, 王召巴, 张瑞, 王志斌. 一种基于两块PEM调制器的光谱测量方法[J]. 光谱学与光谱分析, 2017, 37(9): 2966. LI Shi-wei, WANG Zhao-ba, ZHANG Rui, WANG Zhi-bin. Spectral Measurements Based on Difference Frequency Modulation of Two PEMs Modulators[J]. Spectroscopy and Spectral Analysis, 2017, 37(9): 2966.

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!