Влияние скорости перестройки частоты диодного лазера на форму контура линии поглощения при измерении малых концентраций во внешнем резонаторе с неосевым вводом излучения

The asymmetry of the recorded contours of the absorption lines of water vapor in a quartz tube at room temperature at pressures of 0.03-1 Torr was investigated. The measurements were carried out using the method of diode laser spectroscopy with an external optical cavity. In order to accurately define narrow contours of absorption lines off-axis alignment of the resonator was used. The measurements were carried out with different laser frequency tuning rates of 0.1-0.8 cm -1 /ms with mirrors with 99 and 99.98% reflectivity and different directions of laser frequency tuning. Line asymmetry occurs due to the time delay of radiation inside the cavity. The results of numerical modeling taking into account the filling of the cavity with laser radiation and its decaying in time at the cavity output are in good agreement with the experimental data.