Interference Photolithography Produces Photonic Crystals

A team from Pennsylvania State University in University Park has developed an interference-photolithography method to produce 2-D photonic crystal structures. The scientists fabricated the 0.8- to 2.0-µm-period titania arrays by exposing a titanium-containing monomer film to 355-nm, 15-ns pulses from an Nd:YAG laser from Spectra-Physics in Mountain View, Calif., filtered through a three-grating interference mask. They then rinsed the arrays with methanol and calcinated them at 575 °C.

The researchers say this simple and relatively inexpensive technique can produce various array structures by employing different grating mask patterns, potentially making it a boon to integrated photonic circuit applications. Specifically, it may especially benefit fabrication of photonic crystal waveguides and microcavity lasers. The results of the work were reported in the Nov. 12 issue of Applied Physics Letters.