| 摘要 |
PURPOSE:To perform AFC characterized by a high speed response by providing a light path of exclusive use for automatic frequency control (AFC), by driving a programmable constant current power source by a signal of detected laser radiation having a varying wavelength, and varying a laser current. CONSTITUTION:The light from a laser element 5 is reflected by a parabolic mirror 26, passes through a beam splitters 19 and 23, and is irradiated into a gas 30 in the light path to be measured. The light further goes through a corner cube 28, the beam splitter 23, and a parabolic mirror 27. Then, a signal which is detecred by a detector 6 is processed by a microcomputer 7, and imputted into a recorder 16 or displayed on a display 17. Thus the gas concentration is detected. The optical system comprising a gas cell 1 wherein the gas concentration is already known and a detector 4 and the signal processing system from an amplifier 10a to A/D converters 14a and 15a are responsible for AFC of the laser frequencies. By the optical system comprising the detector 6 as a main body and the signal processing system from an amplifier 10b to A/D converters 15b and 14b, a laser power and its differentiated value are taken out and processed by the microcomputer 7, and the concentration of the gas 30 is measured and evaluated. |
