Photonic Crystals with a Defect Fabricated by Two-Photon Polymerization for the Infrared Spectral Range

Victoria Paige Stinson,Glenn Boreman,Tino Hofmann,Serang Park,Micheal Mclamb

doi:10.3390/opt2040027

Abstract

One-dimensional photonic crystals composed of alternating layers with high- and low-density were fabricated using two-photon polymerization from a single photosensitive polymer for the infrared spectral range. By introducing single high-density layers to break the periodicity of the photonic crystals, a narrow-band defect mode is induced. The defect mode is located in the center of the photonic bandgap of the one-dimensional photonic crystal. The fabricated photonic crystals were investigated using infrared reflection measurements. Stratified-layer optical models were employed in the design and characterization of the spectral response of the photonic crystals. A very good agreement was found between the model-calculated and measured reflection spectra. The geometric parameters of the photonic crystals obtained as a result of the optical model analysis were found to be in good agreement with the nominal dimensions of the photonic crystal constituents. This is supported by complimentary scanning electron microscope imaging, which verified the model-calculated, nominal layer thicknesses. Conventionally, the accurate fabrication of such structures would require layer-independent print parameters, which are difficult to obtain with high precision. In this study an alternative approach is employed, using density-dependent scaling factors, introduced here for the first time. Using these scaling factors a fast and true-to-design method for the fabrication of layers with significantly different surface-to-volume ratios. The reported observations furthermore demonstrate that the location and amplitude of defect modes is extremely sensitive to any layer thickness non-uniformities in the photonic crystal structure. Considering these capabilities, one-dimensional photonic crystals engineered with defect modes can be employed as narrow band filters, for instance, while also providing a method to quantify important fabrication parameters.

Highlights

This enables the fabrication of photonic crystals from a single dielectric material using alternating layers of high- and low-density [11]
We demonstrate the successful fabrication of one-dimensional photonic crystals with defects that induce narrow transmission bands centered within the photonic bandgap using two-photon polymerization from a single monomer
A one-dimensional photonic crystal with a solid, compact, defect layer was successfully fabricated via direct laser writing with two-photon polymerization

Summary

Introduction

This enables the fabrication of photonic crystals from a single dielectric material using alternating layers of high- and low-density [11]. Experimental data and stratified-layer optical model calculations reveal that that the induced defect modes are extremely sensitive to the layer thickness uniformity of the photonic crystal. One-dimensional photonic crystals composed of alternating layers of high- and lowdensity (see Figure 1) were designed using stratified-layer optical model calculations (WVASE32, J.A. Woollam, Co., Lincoln, NE, USA).

Results

Conclusion