Research On The Error Theory And Application Of The Real-time Computer-generated Holograms

Computer-generated holograms (CGH) are widely used in optical testing and metrology, as the CGH is capable of producing diffractive wavefront with any desired shape. Since CGH is not real-time available, many scholars are studying the real-time applications of CGH with modern display devices, such as liquid crystal display(LCD), The applications include, real-time pattern recognition using liquid crystal display based joint transform correlator, CGH interferometric technology for anti-counterfeiting, and real-time application of Furrier transform CGH. Now, real-time CGH is becoming a study focus. The discrete structure of LCD, errors of the hologram fabrication processes and design of CGH, such as pattern distortion and substrate figure errors of LCD, cause errors in the re-constructed diffractive wavefront. This dissertation studies on these errors and real-time application of computer-generated holograms are studied in several respects.According to the theory of computer-generated holograms, using modern optical display devices, such as liquid crystal display and digital micromirror device(DMD), computer-generated holograms are shown real-time, and are used in several optical experiments. Errors of the real-time computer-generated holograms, including substrate figure errors and pattern distortion, are discussed. By experiment, the change of wavefront sensitivity functions of zero- and first-order diffraction beam is tested. In the mean time, experimental result is compared with theory data, with the two agreeing well. The construction and work mechanism of the liquid crystal display and DMD, the characteristic of optics transmission and phase or amplitude modem are studied. The experiment system to detect phase and amplitude of output wavefront is designed, and used to do experiment, setting up the base of controlling LCD real-time. On the theory of real-time CGH, using LCD, spherical and helical wavefronts are produced real-time, and compared with wavefront whose CGH is recorded by film. An aspheric is tested with real-time CGH. The application of the real-time CGH using LCD and DMD as record substrate is studied, such as testing sphere or aspheric by Ronchi test with real-time CGH. And light beam scanner of scanning microscope is made with real-time CGH, improving the property of scanning microscope.