Multiple-pass nondiffuse holographic interferometry

• Published in: IEEE journal of quantum electronics Vol. 6; no. 1; pp. 41 - 44
• Main Authors: Weigl, F., Friedrich, O., Dougal, A.
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.1970
• Subjects: Holographic optical components; Holography; Laser beams; Mirrors; Optical films; Optical interferometry; Optical pulses; Optical sensors; Spatial resolution; Testing
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.1970.1076311

The sensitivity of nondiffuse double-exposure holographic interferometry can be increased for the case of transparent experimental media if the test beam of the interferometer is multiply passed through the experimental medium. This can be accomplished with fairly high spatial resolution if the experimental medium is placed within a lossy optical cavity. The cavity serves to generate a number of component test beams, each one having passed through the experimental medium a different number of times. If the cavity is sufficiently long that successive test beam components are no longer mutually coherent, an off-axis hologram can be formed with a single component by matching the path lengths of the reference beam and the test beam component in question. This allows one to record double-exposure holographic interferograms with increased sensitivity. An experimental arrangement that has produced interferograms with six times the normal sensitivity is described, and the limitations of the technique are discussed.