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Free-standing tantalum pentoxide waveguides for gas sensing in the mid-infrared

Free-standing tantalum pentoxide waveguides for gas sensing in the mid-infrared
Free-standing tantalum pentoxide waveguides for gas sensing in the mid-infrared
Typical applications of integrated photonics in the mid-infrared (MIR) are different from near-infrared (telecom) range and, in many instances, they involve chemical sensing through MIR spectroscopy. Such applications necessitate tailored designs of optical waveguides. Both cross-sectional designs and processing methods of MIR waveguides have been a subject of extensive research, where material transparency and substrate leakage of guided modes have been the most common challenges. Both these challenges can be solved simultaneously with air-suspended waveguides. In this paper, tantalum pentoxide (Ta2O5, tantala) thin films deposited on silicon were tested for two different dry under-etching procedures, XeF2 and SF6 plasma, with both of them facilitating selective removal of silicon. We analyze the advantages and limitations of these two methods and optimize the processing for fabricating membranes with arbitrary length and cross-sectional aspect ratio over 300. The performance of these high-aspect-ratio membranes as a framework for single-mode waveguides is rigorously analyzed at 2566 nm wavelength. With tantala being transparent up to 10 µm wavelength, such waveguides are particularly well suited for gas sensing in MIR.
2159-3930
3111-3124
Vlk, Marek
9c00e823-44fc-48cb-8ced-f3f906077335
Datta, Anurup
a9dcab9b-3b5a-4ef7-bfcb-57242b48c267
Alberti, Sebastián
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Murugan, Ganapathy Senthil
a867686e-0535-46cc-ad85-c2342086b25b
Aksnes, Astrid
1fb962a8-aa14-45fb-a328-d7efe5813879
Jagerska, Jana
c77f075d-7018-4703-8745-ed4cd6398228
Vlk, Marek
9c00e823-44fc-48cb-8ced-f3f906077335
Datta, Anurup
a9dcab9b-3b5a-4ef7-bfcb-57242b48c267
Alberti, Sebastián
e9cdccc9-9342-4377-a0d8-82d33ccbfde4
Murugan, Ganapathy Senthil
a867686e-0535-46cc-ad85-c2342086b25b
Aksnes, Astrid
1fb962a8-aa14-45fb-a328-d7efe5813879
Jagerska, Jana
c77f075d-7018-4703-8745-ed4cd6398228

Vlk, Marek, Datta, Anurup, Alberti, Sebastián, Murugan, Ganapathy Senthil, Aksnes, Astrid and Jagerska, Jana (2021) Free-standing tantalum pentoxide waveguides for gas sensing in the mid-infrared. Optical Materials Express, 11 (9), 3111-3124. (doi:10.1364/OME.430994).

Record type: Article

Abstract

Typical applications of integrated photonics in the mid-infrared (MIR) are different from near-infrared (telecom) range and, in many instances, they involve chemical sensing through MIR spectroscopy. Such applications necessitate tailored designs of optical waveguides. Both cross-sectional designs and processing methods of MIR waveguides have been a subject of extensive research, where material transparency and substrate leakage of guided modes have been the most common challenges. Both these challenges can be solved simultaneously with air-suspended waveguides. In this paper, tantalum pentoxide (Ta2O5, tantala) thin films deposited on silicon were tested for two different dry under-etching procedures, XeF2 and SF6 plasma, with both of them facilitating selective removal of silicon. We analyze the advantages and limitations of these two methods and optimize the processing for fabricating membranes with arbitrary length and cross-sectional aspect ratio over 300. The performance of these high-aspect-ratio membranes as a framework for single-mode waveguides is rigorously analyzed at 2566 nm wavelength. With tantala being transparent up to 10 µm wavelength, such waveguides are particularly well suited for gas sensing in MIR.

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More information

Accepted/In Press date: 9 July 2021
e-pub ahead of print date: 23 August 2021
Published date: 23 August 2021
Additional Information: Publisher Copyright: © 2021 OSA - The Optical Society. All rights reserved.
Venue - Dates: 47th Micro and Nano Engineering Conference, Turin and Online, Turin, Italy, 2021-09-20 - 2021-09-23

Identifiers

Local EPrints ID: 451069
URI: http://eprints.soton.ac.uk/id/eprint/451069
ISSN: 2159-3930
PURE UUID: 9bac0697-2a63-4235-b3a6-18b9ce09b5bd
ORCID for Ganapathy Senthil Murugan: ORCID iD orcid.org/0000-0002-2733-3273

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Date deposited: 07 Sep 2021 16:30
Last modified: 17 Mar 2024 03:03

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Contributors

Author: Marek Vlk
Author: Anurup Datta
Author: Sebastián Alberti
Author: Astrid Aksnes
Author: Jana Jagerska

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