ELECTRONIC SHEAR INTERFEROMETRY - APPLICATION OF A (DOUBLE-) PULSED-LASER

The use of a double-pulsed laser in interferometric metrology relaxes the stability requirements for the experimental setup. The use of such a laser also makes it possible for one to study high-speed dynamic processes. We justify the use of a double-pulsed laser in electronic shear interferometry. We show how image subtraction can be applied to produce high-quality fringe patterns without a special aperture design. The fringe visibility is studied theoretically and is compared with the fringe visibility obtained when the closely related television-holography technique is used. The new double-pulse subtraction technique offers the possibility of compensation for laser intensity fluctuations that can affect the fringe visibility significantly in pulsed electronic shear interferometry.