Holographic lens array and method for making the same

Abstract

A novel hologram functioning as a multiple lenslet array of high density in which the lenslets have selected small spacings and relatively long focal lengths is disposed in a holographic data recording system to provide an object beam along a selected axis. Using the holographic lens array, a data hologram may be recorded with improved uniformity between data points, efficiency, hologram illumination, and with minimization of data beam blockage. In preparing the novel hologram, a coherent object beam may be used to define a plurality of sources for simultaneous recording of a plurality of lenslets. The lenslets of a refractive precursor array defined by a commercially available fly's eye lens may be illuminated simultaneously, and selected size, shape, spacing and f- number characteristics for the lenslets may be achieved by concurrent optical transformation of the individual beamlets before recording. The precursor array may advantageously be immersed in a surrounding fluid of controllable refractivity, to substantially increase the effective focal length at the precursor lenses, and enable a substantially larger area of each lenslet to be used.