| 摘要 |
An operating value of a first laser parameter of a laser device in a laser absorption spectrometer is optimised. The wavelength of laser device emitted light is adjusted by the first or a second laser parameter. The laser absorption spectrometer comprises a light intensity detector measuring the laser light intensity from the laser device. For each of multiple values of the first laser parameter: the light intensity detector measures light intensity obtained across a range of second laser parameter values, and an extremum in the light intensity measure and a peak position for the extremum are identified. A range of first laser parameter values is identified within the values of the first laser parameter for which there is a continuous trend in changes to the identified peak position with changes to the first laser parameter. The first laser parameter operating value is set to be within the identified range.
The laser device is either a mid-infrared LD or the difference frequency generated in a PPNL (250) using the output of two near infrared telecommunication laser diodes (210,220) having for example a DFB (220). The wavelength sweep is realized by a corresponding control of temperature and bias current provided to the LD while the absorption peaks of the isotopes to be detected should be in the middle of the individual sweep ranges. |
