One-dimensional diffractive optical element based fabrication and spectral characterization of three-dimensional photonic crystal templates.

We demonstrate improved fabrication precision and provide the first spectral characterization of Woodpile-type photonic crystal templates formed by one-dimensional diffractive optical elements. The three-dimensional periodic structures were produced in thick resist by sequential exposures of two orthogonal diffractive optical elements with an argon-ion laser. The observed crystal motif is shown to closely match the iso-intensity surfaces predicted by the interfering diffracted beams. Near-infrared spectroscopic observations reveal the presence of both low and high energy photonic stopbands that correspond with theoretical predictions in several crystal directions. Numerous high-energy stop bands are further reported along very narrow crystallographic angles that attest to the high periodicity and uniformity of the crystal motif through the full resist thickness and over the large sample area. The optical characterization demonstrates the precise control and facile means of diffractive-optical-element based holographic lithography in fabricating large-area three-dimensional photonic crystal templates, defining a promising medium for infiltration with high-refractive-index materials to create photonic bandgap devices.