Transient deformation measurement with electronic speckle pattern interferometry by use of a holographic optical element for spatial phase stepping

We have used a computer-generated holographic optical element (HOE) with el ectronic speckle pattern interferometry to calculate the interference phase corresponding to the deformation of a test object from a single TV frame. The HOE is a modified crossed phase grating that introduces a known phase c hange between the +/-1 diffracted orders, without being translated. The pro gressive propagation of transient mechanical waves was measured with an rms precision of 2 pi/30. (C) 1999 Optical Society of America.