Patent ID: 10907950

Abstract:
Disclosed are a laser heterodyne interferometric apparatus based on plane mirror reflection and a corresponding method. The interferometric apparatus includes a dual-frequency laser, a first photoelectric receiver, a second photoelectric receiver, a first polarizing beamsplitter, a second polarizing beamsplitter, a third polarizing beamsplitter, a quarter-wave plate, a right angle mirror, an optical compensator, and a measured plane mirror. The method performs heterodyne interferometry with two spatially separated beams of different frequencies and balances the optical path lengths of the measurement beam and the reference beam with the optical compensator. In the method, the measured plane mirror moves back and forth along the propagation direction of the input beams. The disclosure suppresses optical non-linearity and optical thermal drift in laser heterodyne interferometry, simplifies the optical path structure, and improves accuracy of laser heterodyne interferometry.