Three-dimensional phase-shifting electronic speckle pattern interferometry based on a non-cube beam-splitter

A novel Cube Beam-Splitter, called Non-Cube Beam-Splitter (NCBS), is used for three-dimensional phase-shift Electronic Speckle Pattern Interferometry (ESPI). By using the NCBS lights from a tested object and lights from a reference surface can be combined and then interfere each other on a CCD camera when a laser beam illuminates the test object and the reference surface simultaneously. When three laser beams illuminate the test object at different incident angles respectively before and after deformation, three interference fringe patterns are formed. Then three phase maps corresponding to three lasers can be calculated by using phase-shift, by which three displacement components are completed. The principle of the method is presented and proved by a typical three-point bending experiment. Experimental results are offered.