Self-Mixing Interferometry: a Universal Yardstick to Measure Almost Everything
11/06/2014
El proper dimecres 18 de Juny el professor Silvano Donati impartirà una sessió tècnica al CD6. Silvano Donati del Department of Electronics University of Pavia (Itàlia) és IEEE i OSA Life Fellow i una figura mundial en el món dels sensors electro-òptics i en particular de la interferometria de self-mixing.
La sessió tècnica titulada “Self-Mixing Interferometry: a Universal Yardstick to Measure Almost Everything” tindrà lloc a l'edifici del CD6 al Campus de la UPC a Terrassa.
Abstact: In this talk, we start with a theoretical introduction to mutual- and self-coupling phenomena in laser oscillator, and then describe in details the principle of operation of self-mixing interferometer, a new coherent configuration for the measurement of dimensional and kinematic quantities such as: displacement, distance, vibration amplitude, thickness, and angle, and also physical quantities like: coupling factors, line width, alfa-facto index of refraction. In the measurement arrangement, the laser
undergoes self-injection at weak level, leading to an amplitude and frequency modulation driven by external optical path length. Then we will describe the developments of a displacement-measuring instrument, first by using the up/down counting of mode hops, then extending the principle of measurement to the case of a diffuse target, reflecting back a field affected by the speckle-pattern statistics. Third, we will report on the successful implementation of two-channel (or, referenced) vibrometer, based on analogue processing of the self-mix signal, in which the speckle-related amplitude errors are removed thanks to a servo-loop concept, and the instrument is capable of true differential operation, on diffuse surface, like a normal optical interferometer operates on legs ending
with reflective surfaces. A survey of perfomance achieved in different design will conclude the talk.
La sessió tècnica titulada “Self-Mixing Interferometry: a Universal Yardstick to Measure Almost Everything” tindrà lloc a l'edifici del CD6 al Campus de la UPC a Terrassa.
Abstact: In this talk, we start with a theoretical introduction to mutual- and self-coupling phenomena in laser oscillator, and then describe in details the principle of operation of self-mixing interferometer, a new coherent configuration for the measurement of dimensional and kinematic quantities such as: displacement, distance, vibration amplitude, thickness, and angle, and also physical quantities like: coupling factors, line width, alfa-facto index of refraction. In the measurement arrangement, the laser
undergoes self-injection at weak level, leading to an amplitude and frequency modulation driven by external optical path length. Then we will describe the developments of a displacement-measuring instrument, first by using the up/down counting of mode hops, then extending the principle of measurement to the case of a diffuse target, reflecting back a field affected by the speckle-pattern statistics. Third, we will report on the successful implementation of two-channel (or, referenced) vibrometer, based on analogue processing of the self-mix signal, in which the speckle-related amplitude errors are removed thanks to a servo-loop concept, and the instrument is capable of true differential operation, on diffuse surface, like a normal optical interferometer operates on legs ending
with reflective surfaces. A survey of perfomance achieved in different design will conclude the talk.
