1次元ホログラフィに基づくフレネルホログラム作成条件の決定法

抄録

In case of construction of complex amplitude acoustical holograms, intensity of diffracted wave and spatial frequency distribution on the observing plane which are caused by an arbitrary aperture are not presumed conventionally. If the diffraction patterns (intensity and spatial frequency distributions) of the diffracted waves can be assumed, them the hologram area and sampling intervals are automatically decided. To resolving the problem, a paraxial ray approximated equation is introduced, which indicates relationship between diffraction pattern due to an arbitrary aperture and that due to a model aperture in the Fresnel region, and preliminally calculated Fresnel diffraction patterns due to a model aperture are plotted on graphs. Using these graphs, diffraction patterns on the observing plane due to an arbitrary width aperture are conveniently obtained, so the requested hologram area and the sampling intervals are easily decided using a parameter 'm' (a ratio of (model aperture width/arbitrary aperture width)). These results are useful especially for long wave holography, such as underground, underwater and in air circumstance investigations, architectural acoustics and spatial filtering technologies.