A five-zone binary phase filter applied to increase the recording depth of near-field SIL optical storage system

A novel filter with five-zone binary phase pupil function is designed for improving the recording depth of near-field hemispheric solid immersion lens optical storage system. Numerical results show that with the increase of the distance from the air-disk interface the variations of the spot size and intensity of the recording spot are slower with the design filter than that without any filters. This illustrates that the designed filter can evidently increase the recording depth of near-field hemispheric solid immersion lens optical storage system.