| 摘要 |
PURPOSE: To obtain a heterodyne intermediate frequency ten or more time as high as one obtained through a prior art device by a method wherein an optical frequency shifter which is capable of shifting the frequency of one of two isolated optical beams different from each other in axial mode is provided. CONSTITUTION: Laser beams outputted from a laser ray source 1 are vertical to each other in plane of polarization. The laser beams enter a mode isolation optical system 2 such as a polarized beam splitter or the like to split into two laser beams 101 and 103 different from each other in plane of polarization, the laser beam 101 enters an optical frequency shifter 3 to be shifted in frequency by a frequency of fx into a laser beam 102, and the laser beam 102 is outputted. In result, a beat frequency of fi +fx between the laser beams 102 and 103 is obtained. A frequency difference fi +fx between the two projected laser beams nearly ten times as high as a frequency difference fx of a conventional device can be obtained as a heterodyne intermediate frequency. |
