Single-step optical realization of bio-inspired dual-periodic motheye and gradient-index-array photonic structures

Abstract

This Letter demonstrates a single-step optical realization method for hexagonal and square lattice-based dual periodic motheye and gradient-index-array photonic structures over large areas. Computed phase mask of gradient interference patterns are used as inputs to a phase-only spatial light modulator (SLM), and the first-order diffracting beams are coherently superposed with the help of a 2f-2f Fourier filtering setup to avoid complex optical geometry for generation and control of individual beams. The simulated interference patterns are verified experimentally through a CMOS camera. The fabricated micro-structures on a positive photoresist are shown to have a major periodicity of 638 μm and minor periodicity of 25.2 μm, with the air hole diameter varying from 22.7 to 6.9 μm along the X and Y axes. The depth of the fabricated structure gradually varies from 4.203 μm at the center to 1.818 μm at the corner. These structures may be scaled down to submicron features that can show improved anti-reflection properties for solar energy harvesting and GRIN lens for optical wavelength region.

A review on the progress of nanostructure materials for energy harnessing and environmental remediation

“…This moth eye framework provided a dramatic enhancement in the external quantum efficiency. Meanwhile, free absorption of electromagnetic spectrum was obtained which improved the surface plasmon resonance activity [267,268]. Thus, above-discussed nature inspired nanostructure harbored with carbonaceous materials, surface modified semiconductors, and noble metal would be a new future perspective to devise intelligent energy materials.…”

Holographic Fabrication and Optical Property of Graded Photonic Super-Crystals with a Rectangular Unit Super-Cell

“…The use of a phase mask or single reflection optical element has greatly reduced the complexity and has improved the mechanical stability of the optical setup [13][14][15][16][17][18][19]. Recently, SLM has been used as an electrically adjustable phase mask for the interference lithography [20][21][22][23][24][25][26][27]. The computer-generated hologram method can be used for the fabrication of the desired structure using SLM.…”

Design of an Electrically Tunable Micro-Lens Based on Graded Photonic Crystal

“…A micro-lens with adjustable focal length (FL) is designed, which is composed of GPCs and LCs. This design can be made quickly by a single-step interference-based approach [25]. The GPCs are kinds of square lattices with polymer rods in the background of LCs.…”