Rapid prototyping of two-dimensional photonic crystal devices by a dual beam focused ion beam system

Abstract

We report on the fabrication of two-dimensional photonic crystals (2D-PC) structures by means of a focused ion beam (FIB), which is an alternative process well suited for the fast prototyping of high quality 2D-PC devices. Through FIB process the removal of materials is achieved without the use of a patterned resist mask. We have fabricated two different short in-plane cavities: the ridge geometry configuration, obtained through trenches etched down to the bottom cladding by means of a FIB process, and a second identical cavity terminated by a 2D-PC back mirror consisting of a triangular lattice of air holes in GaAs slab. Both the ridge cavity and the photonic crystal cavity have been optically characterized by detecting their edge-emitted photoluminescence. As expected, by virtue of its higher back mirror reflectivity leading to lower cavity losses, the 2D-PC cavity shows the occurrence of amplified spontaneous emission at an excitation power density three times lower than in the standard ridge cavity.