In this letter, we proposed an innovative laser self-mixing interferometer (SMI) with a reflection-type two-dimensional (2D) grating for three-dimensional (3D) dynamic displacement sensing. When the beams emitted by three lasers are incident on a reflective 2D grating with auto-collimation diffraction angles, the diffracted beams will return into the lasers along the original path, thus generating self-mixing interference effect in each laser. In order to obtain higher measurement resolution, phase-modulation technique is applied to the proposed interferometer. The operating principle for the proposed system has been demonstrated in detail. Measurement results show that our method is capable of sensing 3D dynamic displacement with resolution of nanometer level. The SMI presented in this letter has the merits of high resolution, compact system configuration and straightforward operation.

中文翻译：

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激光自混合干涉仪，用于三维动态位移传感

在这封信中，我们提出了一种具有反射型二维（2D）光栅的创新型激光自混合干涉仪（SMI），用于三维（3D）动态位移传感。当三个激光器发出的光束入射到具有自准直衍射角的2D反射光栅上时，衍射光束将沿着原始路径返回到激光器中，从而在每个激光器中产生自混合干涉效应。为了获得更高的测量分辨率，将相位调制技术应用于所提出的干涉仪。拟议系统的工作原理已得到详细说明。测量结果表明，我们的方法能够感知纳米级分辨率的3D动态位移。这封信中介绍的SMI具有高分辨率的优点，