One form of precision metrology used in the Electro- optics Group requires stable illumination of the object under investigation. Stabilized white light sources are typically used for small areas of interest, but larger areas cannot be sufficiently illuminated in a practical manner by such sources.
Laser diodes are desirable due to their compact nature and high power.
Several forms of speckle compensation have hence been developed in order to take advantage of the benefits of these available light sources while avoiding their deleterious effects. Speckle Compensation Environmentally Robust Interferometry Interferometry has the capability of measuring surface deformations on the order of an optical wavelength. These precise optical instruments are hence typically confined to optical laboratories. Phase-stepping shearography allows measurements of extremely small surface deformations outside of the laboratory. The Electro-optics Group has developed a dynamic light compensation technique to alleviate the problem of specular reflection from a surface.