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https://hdl.handle.net/2142/129634
Description
Title
Characterization of infrared imaging systems
Author(s)
Ashok, Sandhya
Issue Date
2025-05-06
Director of Research (if dissertation) or Advisor (if thesis)
Bhargava, Rohit
Department of Study
Electrical & Computer Eng
Discipline
Electrical & Computer Engr
Degree Granting Institution
University of Illinois Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
Infrared Imaging Systems
Imaging Systems
Characterization
Fabrication
Microfabrication
Fourier Transform Infrared Imaging
FTIR
Abstract
This thesis explores the characterization of infrared (IR) imaging systems by microfabricating and analyzing USAF targets with varying thicknesses (0.6 μm to 5.3 μm) using SU-8 photoresist. The targets were fabricated in a cleanroom environment to ensure controlled conditions and high precision. Designed with well-defined USAF patterns, they served as reliable test samples to assess spectral accuracy and resolution capability due to their tailored and precisely measured parameters. Comparative thickness measurements using surface profilometry (DekTak3ST) and laser confocal microscopy (Keyence VK-X1000) revealed that surface profilometry was more accurate for thin films (< 1 μm) due to challenges in resolving transparent film surfaces via confocal microscopy. High-resolution profiles of USAF targets demonstrated a superior edge quality in laser confocal profiling with 0.08 μm pitch size but were prone to negative artifacts due to the same resolution issue. The Varian 620-IR FTIR imaging system was used to acquire spectra, and 1608 cm⁻¹ peak (aromatic C=C) was analyzed, to evaluate spectral fidelity. While the results followed Beer-Lambert law by showing increasing absorbances for thicker films, thicker films presented baseline linearity challenges. This dataset of well characterized targets provides a strong foundation for validating future IR instrument accuracies as well as IR simulation models.
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