Two-dimensional velocity measurements With self-mixing technique in diode-pumped Yb:Er glass laser

Self-mixing laser Doppler velocimeter based on a two beam geometry scheme is investigated using a single-frequency Yb:Er-doped phosphate glass laser. The geometry allows the observation of a beat mode with optical crosstalk between the two optical paths, giving two major improvements: 1) a precise positioning of the optical head compared to the scattering target; 2) the measurement of both the absolute value of the velocity and the orientation of the speed.