Potential of autodyne lidars for study of the atmosphere

Nowaday usage of laser autodyning, i.e., usage of a laser as a transmitter of probing signal and as the receiver of its frequency shifted echo, is quite attractive area for the lidar community (see, for example, Ref. 1). Such an approach to laser sensing of the atmosphere looks very beneficial since information on atmospheric path losses and on retroreflector (mirror, topographic targets, aerosol) properties is retrieved from characteristics of the laser intracavity field. As a result of intraresonator mixing, the following positives take place: (1) high noise immunity; (2) enhanced sensitivity quite comparable with those achieved at heterodyning; (3) possibility to neglect by short noise of a photodetector; (4) simple lidar design since the same optical path is used for the probing signal and its echo; (5) absence of local oscillator, hence robustness and self-alignness of the lidars; (6) possibility to retrieve a set of optical and dynamic characteristics of the distant retrorflector and atmospheric path from signal measurement.