论文部分内容阅读
提出了一种基于激光多重回馈效应的纳米计量系统,系统采用非准直平凹回馈外腔结构,使在回馈外腔中往返多次的回馈光束返回到激光谐振腔中,形成高阶回馈效应,得到了高密度、类正弦和位相正交的双频激光回馈条纹。条纹的密度为传统弱回馈的几×10倍,而且回馈条纹以激光波长为尺子,具有可溯源性,在没有任何电细分的条件下达到了nm级的光学分辨率。特别地,通过采用双折射双频激光器,获得了两偏振正交的激光回馈条纹,而且两正交偏振回馈条纹间还具有位相差,位相差的大小主要由双频激光器的频差、外腔长以及回馈阶次决定。利用两正交偏振回馈条纹间的位相关系,可用于识别物体的运动方向。与激光干涉仪的比对实验表明,系统的线性度优于5.2×10-5,光学分辨率为10.2nm,量程大于500μm。
A nanometer measuring system based on laser multiple feedback effect is proposed. The system adopts a non-collimating concave-convex feedback external cavity structure so that the feedback light beam which reciprocates many times in the feedback external cavity is returned to the laser resonator to form a high-order feedback effect , Has been high-density, sinusoidal and phase-quadrature double-frequency laser feedback streaks. Stripe density of the traditional weak feedback of several × 10 times, and the feedback stripes to the laser wavelength as a ruler, with traceability, in the absence of any subdivision reached nm optical resolution. In particular, by using birefringent dual-frequency laser, two polarization orthogonal laser feedback stripes are obtained, and the two orthogonal polarization feedback fringes also have a phase difference. The magnitude of the phase difference is mainly determined by the frequency difference of the dual-frequency laser, the outer cavity Long and give feedback order decision. The phase relationship between the two orthogonal polarization feedback fringes can be used to identify the direction of motion of the object. The comparison with the laser interferometer shows that the linearity of the system is better than 5.2 × 10-5, the optical resolution is 10.2nm and the range is more than 500μm.