Photonic bandgap infrared spectrometer

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Infrared (IR) spectroscopy is crucial for identifying molecular fingerprints.
• Existing IR spectrometers can be complex and costly.
• Photonic bandgap (PBG) structures offer unique optical filtering properties.

Purpose of the Study:

• To propose and demonstrate a novel IR absorption spectrometer.
• To utilize a spatially variable PBG structure for IR spectroscopy.
• To enable detection and identification of volatile organic compounds.

Main Methods:

• Fabrication of a PBG structure using thermally evaporated chalcogenide quarter-wave stacks (QWS) with a cavity layer.
• Integration of the PBG structure with a blackbody source and an IR detector.
• Exploitation of the spatially variable transmission peak of the QWS cavity mode as a tunable IR filter.

Main Results:

• Demonstration of an IR-PBG spectrometer capable of identifying IR molecular fingerprints.
• The PBG structure functions as a variable IR filter due to spatial variation of the transmission peak.
• Successful application for the detection and identification of volatile organic compounds.

Conclusions:

• The proposed IR-PBG spectrometer offers a novel approach for molecular identification.
• The use of a spatially variable PBG structure enables tunable IR filtering.
• This technology has potential for sensitive detection of volatile organic compounds.