Keywords

Sol-gel, Optics, Anti-reflective, Nanostructure

Abstract

Research was conducted on broadband, anti-reflective coatings for fused silica and chalcogenide substrates in the infrared region of light. Using chemical preparation to create nano-porous through nano-particle based sol-gel solutions, the alteration of optical properties including refractive index and optical thickness was conducted. The nano-particles can modify the coating surface to allow only zero-order diffracted wave propagation reducing scattering while a partially graded profile of refractive index due surface evaporation lessened the precise phase relations of typical homogeneous coatings. My study of silica and titania sol-gel, and hybrid mixtures of the two were used to obtain the optical properties of the materials. The choice of experiments were rooted in theoretically calculated values, and parameters were selected based on quarter wavelength thickness and square root of refractive index theories of destructive cancellation of rebound waves for reduction of reflection. The fused silica system required anti-reflection in the region of 1.0-1.6 micrometer wavelength of the near-infrared. The base, uncoated transmission in this region is ~91%. A maximum transmission of 98% and no less than 97.3% over the entire region of interest was achieved. The chalcogenide system required anti-reflection in the regions of 1.0-1.6 and 3.5-5.0 micrometers of the near- and mid-infrared. The base, uncoated transmission of these regions is 61.9%. A maximum of 95% transmission was achieved for the 1.0-1.6 region and 87% for the 3.5-5.0 region. Solutions and coatings were characterized by Scanning Electron Microscope, Atomic Force Microscopy, X-ray Photoelectron Spectroscopy, particle size, elipsometry, UV-Vis-NIR, and FTIR to reveal the science behind the development and synthesis of nano optical coatings.

Notes

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Graduation Date

2007

Semester

Spring

Advisor

Seal, Sudipta

Degree

Master of Science (M.S.)

College

College of Engineering and Computer Science

Department

Mechanical, Materials, and Aerospace Engineering

Degree Program

Materials Science and Engineering

Format

application/pdf

Identifier

CFE0001641

URL

http://purl.fcla.edu/fcla/etd/CFE0001641

Language

English

Release Date

May 2007

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

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