Integrated narrowband guided mode resonance photonic filters for advanced mid-infrared microspectroscopy

Liu, Jui-Nung

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https://hdl.handle.net/2142/78776 Copy

Description

Title

Integrated narrowband guided mode resonance photonic filters for advanced mid-infrared microspectroscopy

Author(s)

Liu, Jui-Nung

Issue Date

2015-04-24

Director of Research (if dissertation) or Advisor (if thesis)

Cunningham, Brian T.

Doctoral Committee Chair(s)

Cunningham, Brian T.

Committee Member(s)

• Bhargava, Rohit
• Wasserman, Daniel M.
• Liu, Gang Logan

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Photonic crystal
• Guided resonance
• Infrared spectroscopy

Abstract

Characteristic molecular vibrational absorption wavelengths in mid-infrared (mid-IR) have been discovered for various applications, and as a result, a faster summary of an MIR spectrum can be gained by probing a set of discrete spectral fingerprints only, enabling many applications including fast early cancer diagnostics, real-time spectroscopic observation, on-chip chemical sensing, and simple/compact mid-IR instrumentation. In this ‘discrete-frequency infrared’ (DF-IR) spectroscopy approach, there is no Fourier transform infrared (FT-IR) interferometer that continuously scans a spectrum, and acquisition of spectral information can be made rapidly by combining an MIR detector and a tunable single-peak narrowband light source, such as selective thermal emitters, quantum cascade (QC) lasers, or a combination of a broadband incandescent globar and filters. This thesis explores the DF-IR approach by using photonic filtering that is based on guided mode resonance (GMR). First, a useful analytical framework for optimal design of GMR devices is established based on a sound understanding of the underlying physics, and can be used to complement numerical electromagnetic simulations. Then, guided by this judicious design, the thesis presents experimental realization of high-performance GMR filters in the C-H stretching region (3-4 µm or 2500-3300 cm-1) of the mid-IR, and demonstrates GMR-filter-based DF-IR microspectroscopy for the first time. Last but not the least, this thesis introduces a new type of high-refractive-index photonic filter in the challenging but important molecular fingerprint mid-IR (6-10 µm or 1000-1600 cm-1) that shows behaviors distinct from conventional GMR. The combination of the high-index photonic devices and the recently developed QC emitters is proposed as a novel, promising solution to high-quality DF-IR microspectroscopy.

Graduation Semester

2015-5

Type of Resource

text

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http://hdl.handle.net/2142/78776

Copyright and License Information

Copyright 2015 Jui-Nung Liu

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