| 摘要 |
A Michealson-type self-aligning interferometer utilizes a laser (1) to produce an output beam (20) of light that is split into a signal beam (40) and a reference beam (30). The signal beam (40) is directed through a Bragg-cell (5), for heterodyne detection, and a beam expander (6), for facilitating target acquisition, toward a retroreflector (7) located on a target body (80). The returning signal beam (54) is thereby reflected back through the beam expander (6) and Bragg-cell (5) to the resonance mirror (2) of the laser (1), and is now shifted in frequency by 2 ZETA . The returning signal beam (54) and reference beam (30) are directed into a detector (4) to produce an electrical signal (60). A frequency divider (8) and a phase demodulator (9) extract the phase information (70) of the electrical signal (60) through heterodyne detection, the phase being proportional to the position of the retroreflector (7) and, hence, the target body (80). |
