Centre for Sensors, Instruments and Systems Development

Universitat Politècnica de Catalunya

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Analysis and Control of Speckle Effects in Self-Mixing Interferometry. Application to motor shaft monitoring

Reza Atashkhooei (CD6) presents the results obtained in the analysis of the effects of speckle pattern in self-mixing interferometry and its application to motor shaft monitoring. Below you can find the abstract of the paper presented to teh IEEE Sensors 2011 Conference (Limerick, Ireland). The work was carried out in collaboration with Francisco Azcona (CD6), Usman Zabit (LAAS, Toulouse) and Santiago Royo (CD6).

An analysis of speckle effects in self-mixing interferometry signals has been performed. We will characterize the effect of surface roughness and laser spot size on the speckle modulation of the signal, and we will propose two simple experimental approaches to overcome the amplitude fading induced by speckle effect. Differently to the techniques proposed up to the moment, our first approach uses an adaptive optical element in the form of a voltage programmable liquid lens, which adaptively changes its focal length to modify the speckle pattern. Our second approach combines two laser signals which present different performance parameters. By using any of these simple methods, the introduction of inaccuracies in the measurement process due to speckle is avoided.
CD6 Centre for Sensors, Instruments and Systems Development
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