Patent ID: 11914304
Assignee: THE BOARD OF TRUSTEES OF THE UNIVERSITY OF ILLINOIS
Field: Optics (Instruments)
Classification: CPC G  C | IPC C  G

Claim 0:
1. A method for controlling a density distribution of a three-dimensional photonic crystal template, comprising:
depositing a photoresist composition comprising a photoinitiator homogeneously distributed throughout a volume of the photoresist composition on a substrate;
depositing a plurality of light reflective and/or light absorbing particles on the photoresist composition resulting in at least two areas above the substrate having different amounts of the plurality of light reflective and/or light absorbing particles before irradiating;
irradiating the photoresist composition with at least four laser beams using a multibeam interference lithograph system to generate a periodic interference pattern comprising a periodic pattern of a gradient constructive volume and a destructive volume in an exposed photoresist composition, where an exposure duration is less than 0.3 seconds, and where the photoinitiator is at a concentration greater than a maximum amount that photolyzes in two seconds;
baking the exposed photoresist composition at a fixed temperature and time independent of the exposure duration to form a gradient-like periodic structure comprising a polymerized and gelled photoresist derived from the gradient constructive volume and an un-gelled photoresist in the destructive volume;
dissolving the un-gelled photoresist with a solvent to form an un-gelled photoresist solution; and
washing the un-gelled photoresist solution with a washing solvent from the three-dimensional photonic crystal template such that the three-dimensional photonic crystal template has a density gradient that is proportional to the exposure duration.