Speckle is one of the main obstacles to the application of self-mixing interferometers into practice.
Self-mixing model reflecting speckle is of great theoretical and practical significance in self-mixing interferometry.
Ho Kwang Myong, a researcher at the Faculty of Physical Engineering, has suggested an improved model for a clearer explanation of the effect of speckle on self-mixing signals, and investigated the mechanism of feedback coefficient intensity variation induced by speckle and the effects of the surface orientation on the signals.
First, he built an improved model by replacing the output mirror reflectivity with amplitude feedback fraction in an external cavity and provided equations to calculate the amplitude feedback fraction.
Then, he proved through simulations and experiments that the irregular fluctuation of the speckle affected self-mixing signal is mainly due to the orientation change rather than the longitudinal displacement.
For further information, you can refer to his paper “Improved self-mixing model reflecting speckle” in “Applied Physics B” (SCI).
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