Nanometer displacement real-time measurement system and method based on laser polarization interference

The invention discloses a nanometer displacement real-time measurement system based on laser polarization interference. Comprising an infrared laser, a first polaroid, an iris diaphragm, a first polarization splitting prism, a first 1/4 wave plate, a movable plane mirror, a second 1/4 wave plate, a fixed plane mirror, a third 1/4 wave plate, a depolarization splitting prism, a second polaroid, a second polarization splitting prism, a first photoelectric detector, a second photoelectric detector and a third photoelectric detector. The invention further discloses a nanometer displacement real-time measurement method based on laser polarization interference, nanometer displacement real-time measurement which is simple in structure and low in cost is achieved through single-frequency laser, and the problems that a traditional double-frequency laser interferometer is complex in structure and high in cost are solved. Meanwhile, displacement direction identification is achieved by judging the rotation direction of t