Self-Mixing Interferometry: a Universal Yardstick to Measure Almost Everything
Event details
Date | 07.03.2017 |
Hour | 11:00 › 12:00 |
Speaker | Prof. Dr. Silvano Donati |
Location | |
Category | Conferences - Seminars |
EPFL IMT Distinguished Lecture Series
Abstract: In this talk, we describe 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, angle, and curvature, and also physical quantities like: coupling factors, line width, alfa-factor, and 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 treat development of a displacement-measuring instrument, first by up/down counting of mode hops, then extending the measurement to the case of a diffuse target, reflecting back a field affected by the speckle-pattern statistics. We will report on 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, exemplified by the non-contact detection of a mechanical hysterisis cycle in the stress/strain diagram. Additional example of measurements performed by self-mix will be finally surveyed, i.e., the absolute distance meter, the thickness, angles and return echoes measurements as well as that of linewidth and alpha-factor. An outlook on perspectives and future perspectives of self-mix will conclude the talk.
Bio: Prof. Silvano Donati, Emeritus of University of Pavia, IEEE Life Fellow, OSA Emeritus Fellow. For the research on Selfmix Interferometry, Prof. Donati has been awarded the 2015 "A Kressel Award" by the IEEE Photonics Society. References: ”Developing Self-Mixing Interferometry for Instrumentation and Measurements” Laser and Photonics Review, vol.5 (2011), (DOI) 10.1002/ lpor.201100002, see also the book, S.Donati: Electooptical Instrumentation, Prentice Hall 2004, Chapter 4.
Abstract: In this talk, we describe 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, angle, and curvature, and also physical quantities like: coupling factors, line width, alfa-factor, and 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 treat development of a displacement-measuring instrument, first by up/down counting of mode hops, then extending the measurement to the case of a diffuse target, reflecting back a field affected by the speckle-pattern statistics. We will report on 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, exemplified by the non-contact detection of a mechanical hysterisis cycle in the stress/strain diagram. Additional example of measurements performed by self-mix will be finally surveyed, i.e., the absolute distance meter, the thickness, angles and return echoes measurements as well as that of linewidth and alpha-factor. An outlook on perspectives and future perspectives of self-mix will conclude the talk.
Bio: Prof. Silvano Donati, Emeritus of University of Pavia, IEEE Life Fellow, OSA Emeritus Fellow. For the research on Selfmix Interferometry, Prof. Donati has been awarded the 2015 "A Kressel Award" by the IEEE Photonics Society. References: ”Developing Self-Mixing Interferometry for Instrumentation and Measurements” Laser and Photonics Review, vol.5 (2011), (DOI) 10.1002/ lpor.201100002, see also the book, S.Donati: Electooptical Instrumentation, Prentice Hall 2004, Chapter 4.
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