Complex optical holograms

Abstract

The possibility of dispersion relation application for determination of optical properties of reflecting surfaces with help of complex holograms, formed in a specified frequency band is considered. By means of digital simulation the structures of complex Fresnel holograms of plain objects with metal and dielectric surfaces at several optical wavelengths are investigated. Methods and optical scheme are suggested for the formation of Hartley holograms and the reconstruction from them of images of the objects with complex reflection functions. It is shown that the reflection coefficient and phase variation upon reflection of optical radiation from the object under study can be determined from the intensity of the image reconstructed from Hartley holograms.As was shown in papers [1-3], measurements of the intensities of the two quadrature components of the complex holograms [4] at characteristic points of its interference pattern allow, in contrast to the well-known methods [5,6], determining parameters of the reflected field directly. The present paper is aimed at investigating properties of complex holograms in dependence on the optical characteristics of mirror-reflecting surfaces of planar objects and radiation wavelength [7]. Patterns of complex Fresnel holograms of planar objects with metal and dielectric surfaces have been analyzed through numerical simulation for several optical wavelengths. A possibility is considered for the use of dispersion relations to determine optical characteristics of reflecting surfaces from the complex holograms recorded within a specified frequency band.The layout forming complex Fresnel hologram, shown in Fig.1, includes a source 1 of laser radiation with variable wavelength; optical divider 2; reference 3 and investigated 3′ objects, both placed on the planes of a dihedral angle 7; microscope 4 consisting of objective 8 and eyepiece 9; recorders 6 and 6′ placed on the planes of a dihedral angle 10; reference beams 5 and 5′; a phase-shifting plate 11; and optical divider 12.The complex hologram is obtained in the form of two spaced quadrature components of the interference field on the planes of the dihedral angle 10 as a result of interference of the object wave and two reference waves in phase by π/2 [8].The interference constitutions of the quadrature components of the hologram Г 1 and Г 2 [2], can be determined from the measured transmittance by excluding from these intensity magnitudes of the reference beam and photographic components that are measured individually before forming the complex hologram. In order to find reflection coefficient R of the object surface and phase change θ upon reflection Figure 1. A layout forming complex Fresnel holograms 447 978-1-4244-197 -/08/$25.00 ©2008 IEEE