Optimization of an autodyne laser interferometer for high-speed confocal imaging

Eric Lacot (1) , Wilfried Glastre (1) , Olivier Jacquin (1) , Olivier Hugon (1) , Hugues Guillet de Chatellus (1)

1 OPTIMA-LIPhy - OPTique et IMAgeries [Grenoble]

In autodyne interferometry, the beating between the reference beam and the signal beam takes place inside the laser cavity and therefore the laser fulfills simultaneously the roles of emitter and detector of photons. In these conditions, the laser relaxation oscillations play a leading role, both in the laser quantum noise which determines the signal to noise ratio (SNR) and also in the laser dynamics which determines the response time of the interferometer. In the present study, we have theoretically analyzed the SNR and the response time of a Laser Optical Feedback Imaging (LOFI) setup based on an autodyne interferometer. More precisely, we have compared the images quality of two lasers having the same output power, the same relaxation frequency, but having two different values of the LOFI gain induced by two different values of the laser response time. From this study, we have finally determined the best laser dynamical parameters and the best experimental conditions for high speed imaging at the shot noise limit. Finally, we conclude that a laser diode with a very short response time (in the nanosecond range) seems to be an interesting candidate compared to solid-state microchip laser with a response time of several tens of microsecond. Analytical predictions are confirmed by numerical simulations.

Mots clés: Interferometric imaging; Laser sensors

Domaines: Optique [physics.optics]

Eric Lacot, Wilfried Glastre, Olivier Jacquin, Olivier Hugon, Hugues Guillet de Chatellus. Optimization of an autodyne laser interferometer for high-speed confocal imaging. Journal of the Optical Society of America. A Optics, Image Science, and Vision, 2012, 30 (1), pp.60-70. ⟨hal-00768452⟩