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Technical Discussions
23:03 Jul-08-2020
optical feedback interferometry / Laser Diode Self-Mixing Interferometry

Are any of the experts here aware of the technique of Optical Feedback Interferometry / Laser Diode Self-Mixing Interferometry?
Came across the homepage of VOCALZOOM - http://vocalzoom.com/ , which advertised a vibration sensor - a web page without much details but great advertising. Further search led to AMS Technologies, which also showed only poor technical details but one term which attracted me: Self-Mixing Laser Diode (SMLD) - http://www.amstechnologies.com/fileadmin/amsmedia/AMS_Brochures_2019/Non-contact_Measurement_of_Vibrations_56-19-02.pdf (sensor price <3000€)
A nice YouTube Video illustrated the idea behind: https://www.youtube.com/watch?v=MUdro-6u2Zg
A very simple setup to measure vibrations, speed, rotation, displacement. Further search showed: the technique is used as vibrometer – see e.g. VocalZoom.
I could imagine that it could also become useful as a contact free Ultrasound receiver. E.g. for guided wave applications, air coupled UT.
As the laser diode cavity itself is used as interferometer, it is cheap, can be scaled simply as array etc.
Behind the development is for example Philips – see https://www.researchgate.net/profile/Armand_Pruijmboom/publication/255645351_VCSEL-based_miniature_laser-Doppler_interferometer_-_art_no_69080I/links/55e5910208aecb1a7ccbb8c3/VCSEL-based-miniature-laser-Doppler-interferometer-art-no-69080I.pdf
Too there are some researchers in Italy and France: Michele Norgia, Dep. of Electronics, Information and Bioengineering, Politecnico di Milano, Italy
Thierry Bosch, CNRS, LAAS, and Université de Toulouse, INP, France.
In one of the latest publications Norgia and Bosch refer to LaserUT.
Up to now I have found nothing about this topic in NDT.net. I my eyes there could be a high potential for cheap optical receiver arrays.
Is anybody aware of research in this field?
For further information you may check the following links:
• Self-mixing interferometry and its applications (Yanguang Yu, Yuanlong Fan and Bin Liu)
• Laser feedback interferometry: a tutorial on the self-mixing effect for coherent sensing
• Laser diode self-mixing interferometry for velocity measurements
• Application of self-mixing interferometry for depth monitoring in the ablation of TiN coatings (Ali Gokhan Demir, Barbara Previtali, Alessandro Magnani, Alessandro Pesatori, Michele Norgia)
• AMS _VocalZoom. non-contact measurement of vibrations
• Overview of self-mixing interferometer applications to mechanical engineering (Silvano Donati, Michele Norgia)
• Laser diode self-mixing technique for sensing applications (Guido Giuliani, Michele Norgia, Silvano Donati and Thierry Bosch)
• High-sensitivity vibrometer based on FM self-mixing interferometry (M Norgia, F Bandi, A Pesatori, S Donati)
• Self-mixing Interferometer for Contactless Vibration Measurements (ALESSANDRO MAGNANI, DARIO MELCHIONNI, ALESSANDRO PESATORI, MICHELE NORGIA)
• Self-Mixing Interferometry for Industrial Applications Silvano Donati Michele Norgia


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