CHARACTERIZATION OF LASER DOPPLER VIBROMETERS USING ACOUSTO-OPTIC MODULATORS
Michael Gaitan, Jon C. Geist, Benjamin J. Reschovsky, Akobuije Chijioke
We report on a new approach to characterize the performance of a laser Doppler vibrometer (LDV). The method uses two acousto-optic modulators (AOMs) to frequency shift the light from an LDV by a known quantity to create a synthetic velocity shift that is traceable to a frequency reference. Results are presented for discrete velocity shifts and for sinusoidal velocity shifts that would be equivalent to what would be observed in an ideal accelerometer vibration calibration. The method also enables the user to sweep the synthetic vibration excitation frequency to characterize the bandwidth of an LDV together with its associated electronics.