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Integration of mid-infrared SOI photonics with microfluidics

Integration of mid-infrared SOI photonics with microfluidics
Integration of mid-infrared SOI photonics with microfluidics

This work describes the integration of mid-infrared (MIR) silicon photonics with PDMS microfluidics to perform absorption spectroscopy of IPA-water solutions. The MIR spectral region contains strong absorption bands for many molecules, and photonic devices operating in the MIR can be used in many sensing applications. In this work a preliminary demonstration of a silicon-on-insulator (SOI) device is carried out in which the transmission spectra of different concentrations of water-IPA solutions are measured at wavelengths between 3.725 μm and 3.888 μm. A PDMS microfluidic channel is integrated with the waveguides in order to improve the repeatability of sample handing, reduce reagent volumes and prevent evaporation of the analyte. A microfluidic channel with 3000 x 100 μm cross-section and 30 mm length is bonded to a SOI chip comprising 500 nm thick rib waveguides and a 2 μm thick SiO2 top cladding isolating the waveguide mode from the analyte. Trenches were patterned into the SiO2 cladding to create sensing windows of varying lengths (10 μm to 3mm) along different waveguides. The devices were used to detect an expected IPA absorption peak at 3.77 μm, and concentration as low as 3% IPA in water (by volume) was detected. Further work will focus on increasing the sensitivity of the measurement by using increased interaction lengths, reduction of noise and instability, and on the detection of drugs using transmission measurements over a broader wavelength range.

Concentrations, Microfluidics, Mid-infrared, Spectroscopy, Waveguides
SPIE
Qi, Yanli
e4be1a4a-3af6-44e5-9597-8e41bd10a8b7
Rowe, David J.
a0e0fe82-5e29-42b8-b370-5236a722f015
Mittal, Vinita
fd5ee9dd-7770-416f-8f47-50ca158b39b0
Banakar, Mehdi
ad56fc0a-728c-4abb-8be5-74318bb2758e
Wu, Yangbo
000d8846-20f2-4cea-b496-f6f4b73a171f
Nedeljković, Miloš
b64e21c2-1b95-479d-a35c-3456dff8c796
Wilkinson, James S.
73483cf3-d9f2-4688-9b09-1c84257884ca
Mashanovich, Goran Z.
c806e262-af80-4836-b96f-319425060051
Reed, Graham T.
Knights, Andrew P.
Qi, Yanli
e4be1a4a-3af6-44e5-9597-8e41bd10a8b7
Rowe, David J.
a0e0fe82-5e29-42b8-b370-5236a722f015
Mittal, Vinita
fd5ee9dd-7770-416f-8f47-50ca158b39b0
Banakar, Mehdi
ad56fc0a-728c-4abb-8be5-74318bb2758e
Wu, Yangbo
000d8846-20f2-4cea-b496-f6f4b73a171f
Nedeljković, Miloš
b64e21c2-1b95-479d-a35c-3456dff8c796
Wilkinson, James S.
73483cf3-d9f2-4688-9b09-1c84257884ca
Mashanovich, Goran Z.
c806e262-af80-4836-b96f-319425060051
Reed, Graham T.
Knights, Andrew P.

Qi, Yanli, Rowe, David J., Mittal, Vinita, Banakar, Mehdi, Wu, Yangbo, Nedeljković, Miloš, Wilkinson, James S. and Mashanovich, Goran Z. (2019) Integration of mid-infrared SOI photonics with microfluidics. Reed, Graham T. and Knights, Andrew P. (eds.) In Silicon Photonics XIV. vol. 10923, SPIE. 9 pp . (doi:10.1117/12.2507815).

Record type: Conference or Workshop Item (Paper)

Abstract

This work describes the integration of mid-infrared (MIR) silicon photonics with PDMS microfluidics to perform absorption spectroscopy of IPA-water solutions. The MIR spectral region contains strong absorption bands for many molecules, and photonic devices operating in the MIR can be used in many sensing applications. In this work a preliminary demonstration of a silicon-on-insulator (SOI) device is carried out in which the transmission spectra of different concentrations of water-IPA solutions are measured at wavelengths between 3.725 μm and 3.888 μm. A PDMS microfluidic channel is integrated with the waveguides in order to improve the repeatability of sample handing, reduce reagent volumes and prevent evaporation of the analyte. A microfluidic channel with 3000 x 100 μm cross-section and 30 mm length is bonded to a SOI chip comprising 500 nm thick rib waveguides and a 2 μm thick SiO2 top cladding isolating the waveguide mode from the analyte. Trenches were patterned into the SiO2 cladding to create sensing windows of varying lengths (10 μm to 3mm) along different waveguides. The devices were used to detect an expected IPA absorption peak at 3.77 μm, and concentration as low as 3% IPA in water (by volume) was detected. Further work will focus on increasing the sensitivity of the measurement by using increased interaction lengths, reduction of noise and instability, and on the detection of drugs using transmission measurements over a broader wavelength range.

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More information

e-pub ahead of print date: 4 March 2019
Published date: 2019
Venue - Dates: Silicon Photonics XIV 2019, , San Francisco, United States, 2019-02-04 - 2019-02-06
Keywords: Concentrations, Microfluidics, Mid-infrared, Spectroscopy, Waveguides

Identifiers

Local EPrints ID: 431680
URI: http://eprints.soton.ac.uk/id/eprint/431680
PURE UUID: 40ed9627-a0d5-4434-8dc2-6e13d6105428
ORCID for David J. Rowe: ORCID iD orcid.org/0000-0002-1167-150X
ORCID for Vinita Mittal: ORCID iD orcid.org/0000-0003-4836-5327
ORCID for Miloš Nedeljković: ORCID iD orcid.org/0000-0002-9170-7911
ORCID for James S. Wilkinson: ORCID iD orcid.org/0000-0003-4712-1697

Catalogue record

Date deposited: 13 Jun 2019 16:30
Last modified: 16 Mar 2024 04:18

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Contributors

Author: Yanli Qi
Author: David J. Rowe ORCID iD
Author: Vinita Mittal ORCID iD
Author: Mehdi Banakar
Author: Yangbo Wu
Editor: Graham T. Reed
Editor: Andrew P. Knights

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