通过在激光反馈干涉(LFI)系统中引入衍射光栅,提出了一种基于利特罗结构的激光反馈光栅干涉(LFGI)技术,用于一维和二维精密位移的测量。半导体激光器出射的光束以利特罗条件入射至反射式全息光栅,衍射光沿入射光方向返回激光腔后,腔内会发生激光反馈干涉效应。引入正弦相位调制解调技术,高精度地测量一维和二维微位移。利特罗结构和LFGI系统具有自准直性好、结构紧凑、易于操作和系统稳定性高的优点。实验结果表明,利特罗式LFGI系统的位移测量精度可以达到10 nm量级。

By introducing a diffraction grating into the laser feedback interference(LFI) system, we propose a laser feedback grating interferometry (LFGI) based on Littrow configuration for the measurement of one-dimensional and two-dimensional displacement. The beam emitted from the semiconductor laser is incident onto the reflective holographic grating under the condition of Littrow configuration. After the diffracted light returns to the laser cavity in the direction of the incident light, a laser feedback interference effect occurs in the cavity. The sinusoidal phase modulation and demodulation technique is introduced to obtain the one-dimensional and two-dimensional displacement with high precision. The Littrow configuration and LFGI system have the advantages of great self-collimation, compact structure, easy operation and high stability. The experimental results show that the displacement measurement accuracy of the Littrow LFGI system can reach the order of 10 nm.