We report laboratory target vibration measurements that use an easily aligned and adjusted fiber-based 1.5-μm heterodyne lidar. The targets are simple spherically curved retroreflectors with well-controlled vibration frequencies and amplitudes. A rotating ground-glass screen creates Gaussian speckle. We wish to understand the modulated and fast-fading lidar returns seen from real targets. We frequency demodulated the recorded laboratory data by phase differencing to provide estimates of dφ/dt, where φ is the phase of the received carrier-plus-noise phasor. Experimental results for signal strength and signal-to-noise ratio, for specific target modulation parameters, agree well with our recently developed dφ/dt correlation-function theory.
© 2003 Optical Society of America
(120.7280) Instrumentation, measurement, and metrology : Vibration analysis
(280.0280) Remote sensing and sensors : Remote sensing and sensors
(280.3420) Remote sensing and sensors : Laser sensors
Christopher A. Hill, Michael Harris, Kevin D. Ridley, Eric Jakeman, and Peter Lutzmann, "Lidar Frequency Modulation Vibrometry in the Presence of Speckle," Appl. Opt. 42, 1091-1100 (2003)