Holographic fabrication of photonic crystals using multidimensional phase masks

Abstract

This paper reports the experimental approaches to the fabrication of two-layer integrated phase masks and the fabrication of photonic crystal templates using the phase mask based on holographic lithography technique. The photonic crystal template is formed by exposing photoresist mixtures to five-beam interference patterns generated through the phase mask. The fabricated phase mask consists of two layers of orthogonally oriented gratings produced in a liquid crystal and photoresist mixture. A polymerization-induced phase separation preserves the grating structure during the exposure. The vertical spatial separation between two layers of gratings produces a phase difference among diffracted laser beams, which enables the holographic fabrication of diamondlike photonic crystal structures. The fabricated photonic crystal structure is consistent with simulations based on the five-beam interference. The two-layer phase mask opens up an opportunity of direct printing photonic structures.

Interference lithography: a powerful tool for fabricating periodic structures

“…13a) [56] differs from the diffraction mask shown in Fig. 12a in that it has a vertical spatial separation between two grating layers which introduces a phase shift difference among the diffracted laser beams [56][57][58] ; . Such a phase mask transmits a portion of a laser output into one zero th -order beam and diffracts the remainder of the beam to generate four first-order beams with differing initial phases.…”

“…b) An SEM image of a 3D microstructure using a single incident laser beam fabricated using the two-layered phase mask in a. The color inset is a simulation of the expected structure [56]. Wave vectors representing the directions of the incident beams in units of =a [77] are not rapid and random defects are inevitable for largearea samples.…”

Laser Interference Lithography—A Method for the Fabrication of Controlled Periodic Structures

“…For conventional transparency, enhancing films widely used in optical and optoelectronic systems, monolayer dielectric films (n, and n < ns) with low refractive index are prepared on a substrate with high refractive index (ns) based on the thin film interference law ( Figure 5 a). Many natural photonic structures are not of the thin film type and have a distinct periodic variation [ 40 , 41 ]. Such functional structures behave differently due to their different scales.…”

Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

“…Multiple exposures of a 1D phase mask may be used to produce complex 3D periodic patterns, such as a woodpile-type structure [122,123]. Alternatively, a multi-layer mask with two orthogonal diffractive gratings [124][125][126] or a single 2D diffractive optical element [127][128][129][130] may be used to produce multiple beams with a single exposure. As a result of the relatively short optical path lengths for the diffracted beams, this method is essentially phase-locked, representing the most interferometrically stable option for MBIL.…”