Nanometer-scale absolute laser ranging: exploiting a two-mode interference signal for high accuracy distance measurements

Ha Duy Phung (1) , Clément Courde (2) , Christophe Alexandre (3) , Michel Lintz (2)

1 Télémétrie Laser
2 ARTEMIS - Astrophysique Relativiste Théories Expériences Métrologie Instrumentation Signaux
3 CEDRIC - LAETITIA - CEDRIC. Traitement du signal et architectures électroniques

Absolute distance measurement with accuracy below the micron scale is important in astronomical optical interferometry. We present here an absolute laser rangefinder which relies on the detection of a two mode interference signal. We exploit the specific signature of the signal to extract both the interferometric and synthetic phase measurements, leading to distance measurement with nanometric accuracy. A resolution of 100 pm has been achieved in 75 μs with a relatively simple laser source. Amplitude to phase coupling in the detection chains turns out to be the largest source of systematic errors. A specific detection scheme is implemented, using optical demodulation of the microwave optical signal, to reduce amplitude-to-phase related systematic errors to below the required level.

Mots clés: Laser ranging; interferometry; microwave optical modulation; amplitude-to-phase coupling

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]; Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

Ha Duy Phung, Clément Courde, Christophe Alexandre, Michel Lintz. Nanometer-scale absolute laser ranging: exploiting a two-mode interference signal for high accuracy distance measurements. OHP2013 colloquium: Improving the performances of current optical interferometers & future designs, Sep 2013, Saint Michel L'Observatoire, France. pp.79-86. ⟨hal-01058879⟩