Title :
Very low frequency Self-Mixing laser Diode vibrometer
Author :
Martini, Giuseppe ; Randone, E. ; Donati, Silvano
Author_Institution :
Dipt. di Ing. Ind. e dell´Inf., Univ. di Pavia, Pavia, Italy
Abstract :
We present an optical vibrometer especially designed to measure small amplitude (hundreds pm to several μm) vibrations at very low frequency, down to 0.01 Hz. The instrument is based on a Self-Mixing Interferometer of the fringe-lock type, to achieve high sensitivity and a wide dynamic range. As compared to previous design based on the same principle, our vibrometer is free from fringe-lock loss due to thermal drift of the laser wavelength; this result is obtained by exploiting a separate DC feedback loop acting on the Laser Diode bias. Experiments show a very good long-term stability, glitch-free operation, with rms error of 100-pm/sqrt(Hz) over a bandwidth from less than 20 Hz to 20 kHz.
Keywords :
laser stability; semiconductor lasers; vibration measurement; DC feedback loop; fringe-lock type; high sensitivity range; long-term stability; optical vibrometer; self-mixing interferometer; self-mixing laser diode vibrometer; thermal drift; very low frequency; wide dynamic range; Diode lasers; Feedback loop; Frequency measurement; Loudspeakers; Optical interferometry; Temperature measurement; Vibrometers;
Conference_Titel :
Sensors, 2012 IEEE
Conference_Location :
Taipei
Print_ISBN :
978-1-4577-1766-6
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2012.6411498
