| 摘要 |
PURPOSE:To improve detection frequency resolution by collimating emitted light beams from a couple of light sources through one condensing optical system, and causing them to illuminate photodetecting element groups through a couple of optical deflection parts and a Fourier transformation optical system. CONSTITUTION:The output light of a semiconductor laser 12 as the 1st light source is passed through the 1st lenslike medium 13, an optical deflection part 14, and the 2nd lenslike medium 15 for Fourier transformation, and the resulting light is detected through the 1st photodetecting element group 16. A semiconductor laser 18 as the 2nd light source, an optical deflection part 19, and the 2nd photodetecting element group 20 are arranged symmetrically to the laser 12, optical deflection part 14, etc., on the center axis 17 of the 1st and 2nd lenslike media 13 and 15. Therefore, deflected light beams focused on the 1st and 2nd photodetecting element groups 16 and 20 are symmetrical on the center axis 17. Namely, the 1st element group 16 detects a signal which has a frequency F0+N (N=0, 1-) and a frequency interval DELTAF. The 2nd element group 20 detects a signal which has an Fp+1/2DELTAF+NDELTAF. |
