Homodyne laser interferometer for displacement measurements

• Main Authors: Shang-jay-Liou, 劉尚杰
• Other Authors: Shyh-Tsong Lin
• Format: Others
• Online Access: http://ndltd.ncl.edu.tw/handle/xh479f

碩士 === 國立臺北科技大學 === 光電工程系研究所 === 104 === This study developed a homodyne laser interferometer for displacement measerments. The system includes a light source module, an interferometer module, and a phase demodulation module. In the system, the light source contains a laser and a polarizer, aligned with its transmission axis at 45 deg. The interferometer modules’s Reference beam as s- waves and test beam for the p- wave.The interferometer modules includes a Michelson interferometer, quarter wave plate, two-dimensional grating and four-quadrant analysis plate.The phase demodulation module includes four-quadrant sensor, analog signal processing circuit and the digital signal processing circuit. After the beams from interferometer through quarter-wave plate and a two-dimensional grating, are divided into four beams. After the four beams through four-quadrant analysis plate will generating four phase difference 90 degrees interference signal.After the four interference signals were received by four-quadrant sensor, we can Calculate the displacement from the phase demodulation mode analysis phase of interference light signals