Photorefractive holographic lenses and applications for dynamic focusing and dynamic image shifting

Wavelength-multiplexed reflective holographic lenses were recorded in a 1-mm-thick Fe-doped LiNbO3 crystal. A simple theoretical model based on Kogelnik’s coupled-wave theory and Kuktarev’s photorefractive-material equations was used to characterize the photorefractive lenses in terms of Bragg-limited field of view, optimum space-bandwidth-product, and wavelength selectivity. Experimental measurement verified the theoretical calculations. An f/3 lens was recorded, and nearly aperture-limited diffraction performance was observed. Applications of wavelength-multiplexed photorefractive lenses were shown by demonstration of dynamic focusing and lateral image shifting.