对于输出频率易受环境干扰的光栅外腔反馈半导体激光器,在利用光栅和电流两通道反馈并进行动态特性优化后,基于原子偏振光谱的无调制稳频系统可极大地抑制低频随机干扰引起的激光频率波动,并使闭环谐振频率扩展到155 kHz。 此时稳频系统可将特征频率在120 Hz处的激光器频率干扰,抑制到开环时的1/13570。利用偏振光谱,还可以测量原子跃迁线中心频率附近小范围内激光频率的起伏,获得激光器对不同频率声致振动激励的声音响应特性,并可对比研究激光器隔音机壳的隔音效果。实验表明,隔音机壳对于不同频率的声音激励,隔音效果可从12.8下降到0.14。这可为机械结构和隔音系统的设计提供实验依据,并可促进声音精密测量的发展。

For grating-feedback extended-cavity diode laser (ECDL) whose output frequency is susceptible to environmental interference, with two channel feedback loops for grating and injection current, the frequency stabilization system based on modulation-free polarization spectroscopy is optimized. Its resonant frequency is extended to 155 kHz. The laser frequency fluctuation caused by low frequency random disturbance under open loop is greatly suppressed. It can be suppressed to 1/13570 at 120 Hz. Now that laser frequency fluctuation near the atomic transition center frequency can be measured by use of the polarization spectra, and the acoustic response characteristics of ECDL are depicted experimentally with the analysis of laser frequency fluctuation and sound stimulant signal. By contrasting the acoustic response characteristics of ECDL with or without the soundproofing case, the sound insulating effect could be mapped directly. Experiment results show that sound insulating effect resulted from different frequency can deteriorate from 12.8 to 0.14. The measurement of insulating effect can also act as the experimental criteria for optimizing the design of laser mechanical structures and sound insulation systems. Furthermore,this system could be helpful for the development of acoustic precise measurement.