Up to now, laser self-mixing interferometry (SMI) has been widely applied to numerous scientific and industry fields. A easily negligible parameter, linewidth enhancement factor \(\alpha \), influences the inclination of SMI signals, and larger \(\alpha \) generally indicates more inclined fringes. It is demonstrated in the paper that solid-state lasers (SSL) have smaller linewidth enhancement factors compared with semiconductor ones, which interrupt the movement reconstruction of external targets. For Nd:YAG SSLs, \(\alpha \) is experimentally analyzed to be around one, resulting in less tilted SMI fringes, and the direction discrimination property of SMI becomes less obvious even when a smooth target supplies more amount of feedback light. In the Nd:YAG SSL scheme and for harmonic vibrations, a simple and effective method is also proposed to obtain the frequency and amplitude information of external targets. Simulations and experiments show that the method can achieve the frequency accuracy within 1% and the amplitude accuracy better than 3%.

到目前为止，激光自混合干涉仪（SMI）已广泛应用于众多科学和工业领域。一个容易忽略的参数，线宽增强因子\（\ alpha \）影响SMI信号的倾斜度，而较大的\（\ alpha \）通常表示更多的倾斜条纹。本文证明，与半导体激光器相比，固态激光器（SSL）具有较小的线宽增强因子，这会中断外部目标的运动重建。对于Nd：YAG SSL，\（\ alpha \）通过实验分析，SMI大约在1左右，从而导致SMI条纹的倾斜更少，即使平滑目标提供更多的反馈光，SMI的方向辨别特性也变得不那么明显。在Nd：YAG SSL方案中，针对谐波振动，还提出了一种简单有效的方法来获取外部目标的频率和幅度信息。仿真和实验表明，该方法可实现1％以内的频率精度，幅度精度优于3％。