A Study of Hologram Recording and Applications.
Abstract:
The report contains the recent results of a continuing study of holographic techniques. The areas covered are dielectric recordings of holograms, holography with low object irradiance, information reduction, applications of hologram interferometry to nondestructive testing, and the application of holography to the imaging of microcircuit patterns. Signal-to-noise ratio and diffraction efficiency of diffuse-signal-beam holograms recorded in dielectric media were investigated theoretically and measured experimentally. Techniques for recording holograms with very low intensity signal beams were investigated, and optimum parameters for hologram construction were determined. Analyses of two types of periodic scatter plates for information reduction were completed, and experimental results are presented. Real-time holographic interferometry was used to detect stress-corrosion cracking in metals. Bond defects in aluminum honeycomb structures were detected by hologram interferometry. The development of pulsed-laser holography and contouring was continued. Use of modulated-reference wave-holography to study diffusely reflecting vibrating objects is discussed, and preliminary investigations for improving interferometry with transparent three-dimensional objects is also reported. In addition, the results of investigating the possibility of imaging high-resolution microcircuit patterns with holography are presented. Author