Absolute distance measurement using heterodyne optical- feedback on Yb:Er glass laser

Absolute distance measurement based on optical feedback using a singlefrequency Yb:Er glass laser is demonstrated via the combination of heterodyne detection and frequency sweep. The technique allows enhancing the sensitivity of the laser response to self-mixing thanks to resonant excitation close to the relaxation oscillation frequency peak. The experimental results on non-cooperative target are in good agreement with the theory and the shape of the resulting signal is analysed both in the temporal and frequency domains considering the specific dynamic of the class B solid-state laser. Suggestions are provided for further improvements on the signal processing. OCIS codes: 120.0120 Instrumentation, measurement and metrology; 140.3480 lasers, diodepumped; 150.5670 range-finding; 290.1350 backscattering.