Aperture Design and Analysis of Nano-Aperture Laser

摘要

Nanometric light source is one of the most important elements in near-field optical system. In this paper the near-field distribution of nano-aperture lasers (NAL) with square and asymmetrical C aperture are characterized by the method of 3D finite-difference time-domain (FDTD). The simulation results theoretically reveal that the output power peak from the asymmetrical NAL is three or four orders of magnitude higher than that from the normal square or round aperture with the comparable light spot size in the near-field region and power throughput is more than unity. The maximum of the field enhancement occurs at the C aperture size corresponding to one third of wavelength. The effects of configuration, aperture dimension, electric field component, polarization and separation in local near field close to the aperture have been investigated theoretically and numerically. The mechanism of electromagnetic field enhancement is also discussed. The asymmetrical NAL with higher throughput may expand the range of applications possible in near-field optics.