Optical Device And Spectroscopy Apparatus

An optical device comprising:

• a first optical system;
• and
• a second optical system, wherein
• the first optical system includes a first light splitting device configured to split measurement light into a first measurement light and a second measurement light and then mix the first measurement light and the second measurement light,
• a first mirror configured to add a first modulation signal to the first measurement light by being moved with respect to the first light splitting device in an entering direction of the first measurement light and reflecting the first measurement light,
• a second mirror configured to reflect the second measurement light, and
• a first light receiving device configured to receive the measurement light including a sample-derived signal derived from a sample and the first modulation signal and output a first light receiving signal, and
• the second optical system includes
• a light source configured to emit laser light,
• an optical modulator configured to add a second modulation signal to the laser light, and
• a second light receiving device configured to receive the laser light including a displacement signal generated by reflection on the first mirror and the second modulation signal and output a second light receiving signal.