Heterodyned self-mixing laser diode vibrometer

摘要: This patent describes a new method for remotely measuring vibration of an object based on laser Doppler vibrometry. The combines external two-pass frequency shifting technique with self-mixed, heterodyne detection to provide compact measurement system that requires only three optical components. A standard diode package, consisting and monitor photodiode, is used emit light detect the scattered signal, lens collimate light, modulator shift frequency. may be or without temperature stabilization. unique design permits objects from range long distances need focusing alignment. Measurements made are characterized by high signal-to-noise ratio, wide dynamic range, simple