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Swept-source OCT using pulsed mid-infrared light
Author(s): Wai Ching Lin; Stephen J. Matcher
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Paper Abstract

A swept-source optical coherence tomography (OCT) system using mid-infrared light is demonstrated using commercially available light source and photodetectors. The light source is a tunable external cavity quantum cascade laser (QCL) with four laser modules and a wavelength range of 5.4μm – 12.8μm. The laser output is pulsed and has a maximum allowable duty cycle of 8%. A thermoelectrically cooled photovoltaic detector with a peak sensitivity at 8μm is configured in a Michelson interferometer setup. Noise from three sources are characterized: the analogue-to-digital converter (ADC), the detectors and the relative intensity noise (RIN). The ADC and the detector have a noise spectral density of 2.8 pW/√Hz and 21.4 pW/√Hz over a bandwidth of 100 MHz respectively; the value of RIN is -102 dB/Hz. The OCT system is used to collect the reflectivity profile of a mirror, which is measured with a signal to noise ratio (SNR) of 17.5 dB. Decreasing the time of sweep from 1s to 200ms has the effect of reducing the SNR by 4 dB.

Paper Details

Date Published: 4 March 2019
PDF: 8 pages
Proc. SPIE 10890, Label-free Biomedical Imaging and Sensing (LBIS) 2019, 108902D (4 March 2019); doi: 10.1117/12.2507933
Show Author Affiliations
Wai Ching Lin, The Univ. of Sheffield (United Kingdom)
Stephen J. Matcher, The Univ. of Sheffield (United Kingdom)


Published in SPIE Proceedings Vol. 10890:
Label-free Biomedical Imaging and Sensing (LBIS) 2019
Natan T. Shaked; Oliver Hayden, Editor(s)

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