Computational analysis of a holographic optical head configuration

The best configuration for holographic optical heads for compact disk players is discussed from the viewpoint of considering the misalignment allowance for head components. Focus-error and trackingerror signals of the proposed head configurations are simulated with a ray-tracing method and by using optical cross transfer function theory. The misalignment allowance for the head components, such as the objective lens, the holographic optical element, and the photodetector, are calculated for several configurations. The misalignment allowance is found to increase greatly when the holographic optical element is placed in close proximity to the objective lens and then when this assembly is moved as a unit.