Abstract

For rainbow holograms, a spatial and spectral extended light source (white light source) is used for reconstruction. The effect of spectral extension on the image blur (color blur) has been analyzed by several authors, ¹-² but the effects of spatial extension or both extensions together have not been studied. In this paper, a new concept of effective width of extended light source, which may be regarded as a characteristic of rainbow holograms, is proposed. It is proved that owing to the existence of two small apertures (slit and viewer's pupil) both the effective area of spatial extension of the light source and the effective range of its spectral extension are significantly limited. Thus the two extensions have approximately equal effects on the image blur. A strip white light source can be used to reconstruct the rainbow hologram without serious degradation of image quality except for the change of apparent properties of the image.

© 1989 Optical Society of America