| AVS 66th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Wednesday Sessions |
| Session EL+AS+EM+TF-WeM |
| Session: | Optical Characterization of Thin Films and Nanostructures |
| Presenter: | Marc Lata, University of North Carolina at Charlotte |
| Authors: | M. Lata, University of North Carolina at Charlotte Y. Li, University of North Carolina at Charlotte S. Park, University of North Carolina at Charlotte M.J. McLamb, University of North Carolina at Charlotte T. Hofmann, University of North Carolina at Charlotte |
| Correspondent: | Click to Email |
of this technology which is based on the two-photon polymerization of suitable monomers [1, 2]. We have
demonstrated that direct laser writing allows the fabrication of structured surfaces to reduce Fresnel reflection
loss in the infrared spectral range while two-dimensional photonic crystals enable optical filters with high spectral
contrast [3, 4]. In combination with the ability to fabricate large scale arrays of uniform structures, two-photon
polymerization could be a disruptive technology for enhancing focal plane arrays in IR imaging systems.
So far, photonic crystals which provide polarization selectivity have not been used for the pixel-based enhancement
of infrared focal plane arrays. Here we explore the form-birefringence found in photonic crystals composed
of arrays of subwavelength-sized slanted micro wires (Fig. 1) for this purpose. The photonic crystals investigated
here were fabricated in a single fabrication step using direct laser writing of an infrared transparent photoresist.
The lateral dimensions of the photonic crystals are comparable to the pixel size of infrared focal plane arrays which
is on the order of some tens of micrometers [5]. We observe a strong contrast under cross-polarized illumination
in the mid-infrared spectral range at w = 1550 cm-1. Finite-element-based techniques are used to optimized the
geometry of the constituents of the photonic crystals to minimize edge effects. We envision laser direct writing as
a suitable technique for the enhancement of focal plane arrays to enable focal-plane polarimeters for the infrared
spectral range.