| 摘要 |
PURPOSE:To obtain the measuring accuracy stabilized for long time in a device for measuring gas concentration by alternatively selectively radiating output light of two longitudinal modes from a laser light source and transmitting or reflecting the laser light in response to the polarized state of the laser output light. CONSTITUTION:High frequency AC voltage is applied to a piezoelectric element 11 to thereby vibrate infinitesimally a reflecting mirror 10 toward an optical axial direction of a resonator. The output light from a laser tube 1 contains polarized lights perpendicular to each other in rapid period by this infinitesimal vibration. When polarizers 12, 13 for passing only one of the polarized lights of the laser output light are disposed outside of reflecting mirrors 9, 10, they operate as light chopper. The polarizers 12, 13 produce intermittent laser lights to cause one output light to be incident into light absorbing cell 6 and the other output light to be incident into a photodetector 8'. |
