Photonic nanojet-enabled optical data storage.

We show that our recently reported microwave photonic jet technique for detection of deeply subwavelength pits in a metal substrate can be extended to optical wavelengths for purposes of high-density data storage. Three-dimensional finite-difference time-domain computational solutions of Maxwell's equations are used to optimize the photonic nanojet and pit configuration to account for the Drude dispersion of an aluminum substrate in the spectral range near lambda= 400 nm. Our results show that nanojet-illuminated pits having lateral dimensions of only 50 nm x 80 nm yield a contrast ratio 27 dB greater than previously reported using a lens system for pits of similar area. Such pits are much smaller than BluRay features. The high detection contrast afforded by the photonic nanojet could potentially yield significant increases in data density and throughput relative to current commercial optical data-storage systems while retaining the basic geometry of the storage medium.