Microoptical two-dimensional devices for the optical memory head of an ultrahigh data transfer rate and density sytem using a vertical cavity surface emitting laser (VCSEL) array

The parallel optical memory system has important advantages for realizing both a fast data transfer rate and high memory capacity since it is based on multibeam recording and a smaller spot size using the vertical cavity surface emitting laser (VCSEL) and a nanoprobe array. The concept, theoretical analysis and fabrication process for the integrated VCSEL nanoprobe array head are discussed with emphasis on the micro-optical issues such as the improvement of optical efficiency by microlens focusing. The flat-tip nanoprobe structure was successfully prepared with the small metal aperture of 150 nm and 1.25% optical throughput using metal aperture Si or GaP semiconductor nano-probes. To realize better optical throughput in the integrated VCSEL, a special nanoprobe array and a microlens array were developed. The microlens array was prepared using a thermal reflow process of the photoresist and lens shape pattern transfering to the semiconductor nanoprobe bottom face by dry etching. Since this two-dimensional array system requires three-dimensional micro-optical adjustment to focus a very small spot on the recording media, this research can provide guidelines for new micro-optical components in future technology.