Abstract

Computer generated holograms (CGH) offer the possibility of influencing phase and amplitude of a coherent wave in various ways. In the case of Fourier holograms, this can be used for the realization of image projection systems that exhibit some unique properties, e.g. an extremely large depth of focus. However, such CGHs can usually only encode the information for one wavelength since illumination with a different than the design wavelength produces the same far field image, just with a different scaling. To encode information for several wavelengths, advanced techniques have to be applied, involving for example the use of a deeper phase step¹ or the limitation to simplified output signals. Another possibility is the use of stacked CGHs², which allows incorporating typical properties of thick film holograms (angle and wavelength selectivity). Based on this concept we want to present design, fabrication and measurement of a stacked CGH, capable of creating a multicolor image from an RGB-laser beam (Fig. 1).

© 2007 IEEE