介绍了正交线偏振激光器及其在精密测量中的新应用，包括：1) 正交偏振双频激光器，2) 纳米激光测尺(基于频率分裂的激光器两偏振光竞争位移传感器)测量原理，3) 直接利用波片形成频率分裂的波片位相延迟测量原理，4) 激光回馈波片位相延迟测量原理。这些新应用的原理，结构简单，可溯源到光波长。如，纳米激光测尺已在应用中，测量范围12 mm，分辨力79 nm，线性度小于5×10^-5, 基于频率分裂的波片位相延迟测量系统重复性达到0.3′，而激光回馈波片位相延迟测量系统具有在线检测的优点。

Orthogonally linearly-polarized lasers and its new applications in precision measurement are presented, including: 1) orthogonally linearly-polarized lasers, 2) principle for laser nanometer ruler (displacement sensor based on the competition between two polarized lights of the frequency splitting lasers), 3) principle for phase retardation measurement using frequency splitting technology, 4) principle for phase retardation measurement based on laser feedback effects. These novel principles have remarkable characteristics of simple structure, tracing back to optical wavelength. The laser nanometer ruler has been applied in practical occasions, and its performance is as follows: the measurement range 12 mm, resolution 79 nm, and linearity less than 5×10^-5. The repeatability reaches 0.3′ for phase retardation measurement system based on frequency splitting technology. However, laser feedback phase retardation measurement system has the advantage of on-line measuring.