Two-dimensional photonic crystal waveguide obtained by e-beam direct writing of SU8-2000 photoresist

We report on the direct electron-beam patterning of a negative tone resist SU8-2000 for the fabrication of a two-dimensional photonic crystal (2D-PC) waveguide. The high refractive index of the SU8-2000 (about 1.69), its transparency above 360 nm, the good mechanical stability and the possibility of direct patterning by electron-beam lithography, make such resist ideal for the direct realization of high-resolution photonic crystal waveguides. The fabrication of a triangular array of sub-micron pillars (lattice constant of 300 nm and filling factor of 0.35) suitable for the realization of a 2D-PC waveguide on a glass substrate is reported. The energy dispersion diagram, calculated by the plane wave expansion technique, shows that this 2D-PC structure has a small photonic band gap (PBG) for the TM-like modes. (C) 2004 Elsevier B.V. All rights reserved.