Designs and tolerances of numerical aperture 0.8 objective lenses for page-based holographic data storage systems

A two-element aspheric objective lens having numerical aperture (NA) of 0.8 has been designed for media interchangeable holographic recordings. Lens design tolerance of offence against the sine condition and lens aberrations of object and reference beams have been formalized by coupled wave theory and related to diffraction efficiency of holograms. An optimum first-order power arrangement of objective lenses having two air-spaced elements has been identified by minimizing fifth-order aberrations and is further optimized ray-tracebased optimization code. Within tolerances criteria required for media-interchangeable systems, the design has demonstrated high NA of 0.8 with long working distance of 20% of the focal length.