Mid-infrared optical sensing using sub-wavelength gratings

Authors

Brian Hogan, Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork, Ireland and Tyndall National Institute, University College Cork, Cork, Ireland
Liam Lewis, Centre for Advanced Photonics and Process Analysis Cork Institute of Technology, Cork, Ireland, and Tyndall National Institute, University College Cork, Cork, Ireland
Michael McAuliffe, Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork, Ireland
Stephen P. Hegarty, Department of Physical Sciences, Cork Institute of Technology, Cork, Ireland, Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork, Ireland and Tyndall National Institute, University College Cork, Cork, IrelandFollow

Document Type

Article

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Disciplines

Electrical and Computer Engineering | Electromagnetics and Photonics | Physical Sciences and Mathematics

Publication Details

OSA Publishing > Optics Express > Volume 27 > Issue 3

Abstract

Optical sensing has shown great potential for both quantitative and qualitative analysis of compounds. In particular sensors which are capable of detecting changes in refractive index at a surface as well as in bulk material have received much attention. Much of the recent research has focused on developing technologies that enable such sensors to be deployed in an integrated photonic device. In this work we demonstrate experimentally, using a sub-wavelength grating the detection of ethanol in aqueous solution by interrogating its large absorption band at 9.54 µm. Theoretical investigation of the operating principle of our grating sensor shows that in general, as the total field interacting with the analyte is increased, the corresponding absorption is also increased. We also theoretically demonstrate how sub-wavelength gratings can detect changes in the real part of the refractive index, similar to conventional refractive index (RI) sensors.

Recommended Citation

Hogan, B., Lewis, L., McAuliffe, M. and Hegarty, S.P. (2019). Mid-infrared optical sensing using sub-wavelength gratings. Optics Express, 27(3), p.3169. Available at: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-27-3-3169&id=404481 ‌ ‌