Characterization of integrated waveguides by atomic-force-microscopy-assisted mid-infrared imaging and spectroscopy

Gallacher, K. et al. (2020) Characterization of integrated waveguides by atomic-force-microscopy-assisted mid-infrared imaging and spectroscopy. Optics Express, 28(15), pp. 22186-22199. (doi: 10.1364/OE.393748)

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A novel spectroscopy technique to enable the rapid characterization of discrete mid-infrared integrated photonic waveguides is demonstrated. The technique utilizes lithography patterned polymer blocks that absorb light strongly within the molecular fingerprint region. These act as integrated waveguide detectors when combined with an atomic force microscope that measures the photothermal expansion when infrared light is guided to the block. As a proof of concept, the technique is used to experimentally characterize propagation loss and grating coupler response of Ge-on-Si waveguides at wavelengths from 6 to 10 µm. In addition, when the microscope is operated in scanning mode at fixed wavelength, the guided mode exiting the output facet is imaged with a lateral resolution better than 500 nm i.e. below the diffraction limit. The characterization technique can be applied to any mid-infrared waveguide platform and can provide non-destructive in-situ testing of discrete waveguide components.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Millar, Dr Ross and Paul, Professor Douglas and Gallacher, Dr Kevin
Authors: Gallacher, K., Millar, R. W., Paul, D. J., Frigerio, J., Ballabio, A., Isella, G., Rusconi, F., Biagioni, P., Giliberti, V., Sorgi, A., Baldassarre, L., and Ortolani, M.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Optics Express
Publisher:Optical Society of America
ISSN (Online):1094-4087
Published Online:13 July 2020
Copyright Holders:Copyright © 2020 Optical Society of America
First Published:First published in Optics Express 28(15): 22186-22199
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
171911Engineering Quantum Technology Systems on a Silicon PlatformDouglas PaulEngineering and Physical Sciences Research Council (EPSRC)EP/N003225/1ENG - Electronics & Nanoscale Engineering
305161Germanium Tin Quantum DetectorsRoss MillarRoyal Academy of Engineering (RAE)RF/201819/18/187ENG - Electronics & Nanoscale Engineering
169257GEMINIDouglas PaulEuropean Commission (EC)613055ENG - Electronics & Nanoscale Engineering