Analysis and fabrication of microaperture GaAs-GaAlAs surface-emitting laser for near-field optical data storage

We have proposed a microaperture vertical cavity surface-emitting laser (VC SEL) for use in near-field optical data storage. We carried out the near-fi eld analysis of microaperture VCSEL using two-dimensional (2-D) finite elem ent method. We calculated the distribution of optical near-field generated near a microaperture, and showed that the spot size is potentially smaller than 100 mn, which is less than wavelength by a factor of 8. We fabricated a VCSEL loaded by an An film on the top surface for blocking the emitting l ight and formed a subwavelength-size aperture using focused ion beam (FIB) etch through this film. Single-mode operation was obtained for a microapert ure VCSEL with 3-mum square active region. The differential quantum efficie ncy was increased by a factor of 3 in comparison with that before forming a 400-nm square aperture. We estimated the power density of light radiated f rom a 400-nm square aperture to be 0.17 mW/mum(2). In addition, we measured the near-field distribution of a 200-nm square aperture VCSEL by using a s canning near-field microscope.