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

Abstract

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.

3D Micro‐ and Nanostructures via Interference Lithography

“…The stresses associated with the change in volume can sometimes even lead to either cracking or severe distortion of the template and dimensions can change further if the structure is heated above its glass transition temperature during use or during other high temperature process steps if the structure is part of a system. Detailed modeling, as well as experimental characterization of the fabrication processes have reported shrinkage values of mostly between 7 % to 15 %, [51,[60][61][62][63] the reason for the variation being the well-established fact that the precise shrinkages vary, depending on the exact details of the dose, post-exposure and hard bake cycles, developer and development times as well as the amount of constraint of the structure by substrates, superstrates etc. [51] Anisotropic shrinkage can result in a breaking of the symmetry associated with the structure being fabricated.…”

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

“…In this example, a 1D phase mask diffracts the incident beam into three interfering beams at the exit of the mask. 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.…”

Holographic Fabrication of Three-Dimensional Woodpile-Type Photonic Crystal Templates Using Phase Mask Technique

“…Previous researchers have proposed a method of building a 3D structure using two orthogonal 1D phase masks. (Chan, et al, 2006;Chanda et al, 2006) The beams that propagate through two phase masks will have two log-pile patterns recorded inside the photoresist. If well controlled, a 3D woodpile structure may be piled up by the log-pile structure.…”