New low cost analog self-mixing vibrometer

The proposed sensor is based on a self-mixing interferometer (the laser itself acts as interferometer with the back-reflected light). Its working principle is a sort of unwrap of the interferometric signal: by analog elaborations the jumps of the signal are compensated. The sensor exploits the linearity of a single interferometric fringe, achieving resolution much better than half a wavelength, over a wide dispolacement range. The realized sensor combines a very simple optical setup with a low cost electronic elaboration, allowing excellent performances: 1 mm of range measurement with 35 nm resolution, with 10 kHz bandwidth, for a very low material cost, including the optical and electronics components.