| 摘要 |
PROBLEM TO BE SOLVED: To provide a detector for optically detecting a trace gas content reduced in weight and volume to a ppb (10-9) level, by improving operability and environment resistance of the device. SOLUTION: After a first laser beam having a spectral line in a first wavelength area and a second laser beam having a spectral line in a wavelength area of a shorter/longer wavelength than the first wavelength are guided via isolators 11b and 12b and optical fibers 11a and 12a, so as to be multiplexed by means of an optical multiplexer 15, a narrow-band laser beam is produced in a intermediate infrared area (2-9μm) by means of a difference frequency producing nonlinear optical crystal 10, and on the basis of absorption based on the trace gas constituent in the narrow-band laser beam, the trace gas constituent is detected and its quantity is determined. The wavelength area of the second laser beam is varied by means of an external controller 6 so as to be synchronized with the absorption wavelength of the trace gas content to be detected, and consequently, component detection and quantity determination can be carried out.
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