Title

Fabrication and Characterization of Guided-mode Resonance Devices

Date of Completion

January 2010

Keywords

Engineering, Electronics and Electrical|Physics, Optics

Degree

Ph.D.

Abstract

In this dissertation, the fabrication and characterization of various types of guided-mode resonance (GMR) devices are presented. By using frequency-selectivity properties and high sensitivity to parametric variations, these GMR devices are suitable for sensor applications. An agarose-gel based GMR humidity sensor is designed, fabricated, and characterized. Comparison with rigorous diffraction models allows quantification of the gel's refractive index and the attendant relative humidity (RH). For the example sensor structure treated, the resonance wavelength shifts by ∼9 nm on the relative-humidity change from 20% RH to 80% RH. Other chemical- and bio-sensors employing both amplitude and phase detection methods are proposed for more accurate and reliable sensor applications. The phase detection method is promising for higher sensitivity. Typically, GMR devices require 1-3 thin-film layers and can be applied in optical devices. As examples of optical devices, a GMR polarizer and a GMR high reflector are presented. A fabricated GMR polarizer made by electron-beam patterning has high and low transmittance for TE and TM polarizations, respectively, over a ∼40 nm wavelength range. Its experimental extinction ratio is ∼97:1 at a central wavelength of 1510 nm. A GMR high reflector fabricated using a UV-laser-based holographic interferometer has high reflectance (>90%) for TE polarization over ∼130 nm wavelength range and a maximum reflectance of 98.4% at λ ∼ 1560 nm. Additionally, fabrication and characterization of a GMR filter made by soft lithography is presented. As these resonant elements are highly sensitive to parametric variations, it is important to develop methods for their reliable fabrication. Thus, a fabrication process that is consistent and simple is applied, employing an elastomeric mold and a UV-curable organic-inorganic hybrid material. A fabricated GMR filter shows high-efficiency (∼81%), low-sideband reflectance (∼5%), narrow-linewidth (∼4.5 nm) at a resonance wavelength of 1538 nm. Experimental and theoretical results are in good agreement. ^