调制转移光谱光频率标准系统中电光参数的优化研究

根据窄带相位调制光在非线性吸收介质中的近简并四波混频的物理机理,分析了采用电光调制器实现调制转移光谱(MTS)技术的电磁场激励及其动态演化过程,建立了MTS中频率色散谱和吸收谱的理论模型. 研究结果表明:以分子吸收谱线色散谱信号作为频率误差鉴别信号时,系统调制频率取0.72倍谱线线宽附近可以得到最佳的色散信号强度;解调相位的变化对吸收谱的影响很大,但对色散谱而言,解调相位在90°附近的小范围波动对频率误差信号解调效果影响不大;调制度在0.5–1区域可以得到较好的综合稳频效果. 关键词： 光频率标准 调制转移光谱 频率稳定 电光参数优化

Optimization of electro-optical parameter of optical frequency standard system based on modulation transfer spectroscopy technique

According to the mechanism of nearly degeneration four-wave mixing that occurs in a sufficiently nonlinear resonant gaseous medium caused by phase-modulated laser beam, the electromagnetism excitation and dynamic evolvement of modulation transfer spectroscopy(MTS) technique is studied theoretically, and then mathematic models of dispersion spectrum and absorption spectrum of MTS are established too. The results show that when the frequency of modulation signal source is equal to 0.72 times the linewidth of absorption line approximatively, the intensity of dispersion signal reaches a maximum value; it can obtain a better frequency-stabilization result when modulation factor is set to be nearly 0.3; the instability of demodulation phase has a big effect on the absorption spectrum, but on dispersion spectrum, the effect is tiny when the demodulation phase fluctuates near 90°.