Holographically formed three-dimensional Penrose-type photonic quasicrystal through a lab-made single diffractive optical element

Ahmad Harb,Kevin P Chen,Di Xu,Kris Ohlinger,Faraon Torres,Yuankun Lin,Karen Lozano

doi:10.1364/oe.18.020512

Abstract

Large-area three-dimensional Penrose-type photonic quasicrystals are fabricated through a holographic lithography method using a lab-made diffractive optical element and a single laser exposure. The diffractive optical element consists of five polymer gratings symmetrically orientated around a central opening. The fabricated Penrose-type photonic quasicrystal shows ten-fold rotational symmetry. The Laue diffraction pattern from the photonic quasi-crystal is observed to be similar to that of the traditional alloy quasi-crystal. A golden ratio of 1.618 is also observed for the radii of diffraction rings, which has not been observed before in artificial photonic quasicrystals.

Highlights

Photonic crystals have been intensively studied due to the existence of photonic bandgaps in the crystal
Large-area three-dimensional Penrose-type photonic quasicrystals are fabricated through a holographic lithography method using a lab-made diffractive optical element and a single laser exposure
The diffractive optical element consists of five polymer gratings symmetrically orientated around a central opening

Summary

Introduction

Photonic crystals have been intensively studied due to the existence of photonic bandgaps in the crystal. It has been demonstrated experimentally that a complete photonic bandgap can be realized in quasi-periodic lattices of small air holes in materials of low refractive index such as silicon nitride and even glass. This property can enable coupling of light from quasi-crystal device to optical fiber with low optical coupling loss [3]. The photonic quasicrystal template in polymer can be converted into high refractive index materials such as silicon to have a photonic band gap in crystal. We demonstrate the laser holographic fabrication of 3D Penrose-type photonic quasicrystal templates using a lab-made diffractive optical element (DOE) with five gratings orientated five-fold symmetrically. The Laue diffraction pattern from the fabricated photonic crystal shows a pentagon-shaped ghost-face like pattern and a golden ratio of 1.618, which have not been observed before in 3D artificial photonic quasi-crystals

Lab-made diffractive optical element and theoretic description of holography

Experimental results and discussion

Summary