Spectroscopic sensing with resonant cavity-enhanced photodetector arrays

Andrew Bainbridge; Rebecca E. J. Allen; Christopher J. McIndo; Andrew R. J. Marshall

doi:10.1117/12.2606398

5 March 2022 Spectroscopic sensing with resonant cavity-enhanced photodetector arrays

Andrew Bainbridge, Rebecca E. J. Allen, Christopher J. McIndo, Andrew R. J. Marshall

Proceedings Volume 12009, Quantum Sensing and Nano Electronics and Photonics XVIII; 1200903 (2022) https://doi.org/10.1117/12.2606398
Event: SPIE OPTO, 2022, San Francisco, California, United States

Abstract

Resonant cavity-enhanced photodiodes (RCE-PD) have previously been studied for the narrow spectral responses that can be achieved. A narrow response is useful for spectral sensing of a specific absorption line without interference from neighbouring absorption lines. We have designed and fabricated an array of photodiodes that each have a slightly shifted resonance wavelength; so combined photocurrent measurements from all the pixels can be used to not only monitor a single absorption line, but also monitor all absorption lines in a region of the infrared simultaneously. The RCE-PD array concept allows for many substances to be identified and measured, offering much more versatility than a measurement from a single-wavelength RCE-PD. The shift in resonance wavelength is created by inducing a thickness gradient in the epitaxial layers across the wafer. Using this technique, a fabricated 2-inch wafer showed a resonance shift between 1.9 μm and 2.5 μm. A 1D array of pixels was created with a shift in the resonance of 4nm per pixel. Light from a monochromator was used to test the ability of the array to determine the wavelength of the light. For four closely spaced wavelengths, an accuracy of ±2nm was seen.

Conference Presentation

Citation Download Citation

Andrew Bainbridge, Rebecca E. J. Allen, Christopher J. McIndo, and Andrew R. J. Marshall "Spectroscopic sensing with resonant cavity-enhanced photodetector arrays", Proc. SPIE 12009, Quantum Sensing and Nano Electronics and Photonics XVIII, 1200903 (5 March 2022); https://doi.org/10.1117/12.2606398

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