Intracavity detection of absorption with the aid of a tunable semiconductor laser emitting in the middle infrared range

An intracavity spectroscopy method makes use of pulsed PbSnSe lasers with external resonators. The sensitivity (signal amplitude) is increased by a factor exceeding 10². A simple theoretical model is proposed for the description of the behavior of a tunable diode laser with an external resonator when frequency-selective losses are introduced into the resonator.