| 摘要 |
In the present invention, a photodiode 3 includes semiconductor layers 9, 11, 12 and a gate insulation layer 13 which are provided on an embedded insulation layer 8 that is formed on a semiconductor silicon substrate 7, and on the gate insulation layer 13, disposed is a diffraction grating 6 in which a plurality of grooves 6a are formed in a 2D lattice-shape. Measurement light L emitted from a light source device 2 is guided by an optical system 30A that includes a photoelastic modulator 20, and the light is thereby incident on the photodiode 3. The measurement light L is emitted from the light source device 2 in a state of being linearly polarized light having a prescribed wavelength, and the light is transformed at a prescribed frequency by the optical system 30A so that repeated is a state in which two linearly polarized light beams which are orthogonally oriented are formed. An electrical signal from the photodiode 3, in the state in which the measurement light L has become two linearly polarized light beams which are orthogonally oriented, is subjected to lock-in detection. |
