Infrared electronic speckle pattern interferometry at 10 μm

Demonstration of electronic speckle pattern interferometry of opaque scattering objects at 10 mu m wavelength using a commercial thermal-camera is presented for the first time to our knowledge. The idea of using a wavelength longer than the usual visible ones is to render such holographic displacement measurement techniques less sensitive to external perturbations. We discuss some particular aspects of the increase in wavelength to the 10 mu m thermal range. We then show results of in-plane measurement of the rotation of a metallic plate. We applied the phase-shifting technique for quantitative measurements and the results are correlated to countermeasurements with a theodolite.