Burnett, AD

Chowdhury, S

Davies, AG

Dean, P

Linfield, EH

Valavanis, A

White Rose Research Online

This is a repository copy of Spectroscopic diffuse-reflection imaging at a 1.5 m stand-off distance, using a frequency-switchable terahertz quantum cascade laser.White Rose Research Online URL for this paper:http://eprints.whiterose.ac.uk/88245/Version: Accepted VersionConference or Workshop Item:Valavanis, A orcid.org/0000-0001-5565-0463, Dean, P orcid.org/0000-0002-3950-4359, Burnett, AD et al. (3 more authors) (2011) Spectroscopic diffuse-reflection imaging at a 1.5 m stand-off distance, using a frequency-switchable terahertz quantum cascade laser. In: ITQW 2011: The 11th International Conference on Intersubband Transitions in Quantum Wells, 11-17 Sep 2011, Badesi, Sardinia, Italy. This is an author produced version of a paper presented in ITQW 2011: The 11th International Conference on Intersubband Transitions in Quantum Wells.eprints@whiterose.ac.ukhttps://eprints.whiterose.ac.uk/Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Spectroscopic diffuse-reflection imaging at 1.5m stand-off,using a frequency-switchable terahertz quantum cascade laserA. Valavanis, P. Dean, A. D. Burnett, S. Chowdhury, A. G. Davies and E. H. LinfieldInstitute of Microwaves and Photonics, School of Electronic and Electrical Engineering,University of Leeds, Leeds LS2 9JT, United Kingdomemail: a.valavanis@leeds.ac.ukNumerous potential applications exist for imaging at terahertz (THz) frequencies, withinfields including medicine, security, manufacturing quality inspection and chemical sensing.Imaging diffuse reflections from rough or powdered objects offers several advantages over specular-reflection or transmission imaging configurations. Objects of arbitrary thickness may be used,and precise alignment of collection optics is not required, as diffuse reflections spread over alarge solid-angle. Furthermore, commonly-used smooth packaging materials have little effectupon diffuse reflection images. Many substances exhibit strong, material-specific spectral re-sponses to THz radiation and spectroscopic THz imaging has been demonstrated in transmissionand specular-reflection geometries using both time-domain and frequency-domain techniques.However, spectroscopic imaging of the relatively-weak diffuse reflections is challenging, as ahigh-intensity multi-frequency THz radiation source is required, along with a sensitive THzdetector.In this work, we demonstrate four-frequency diffuse-reflection imaging using a frequency-switchable THz quantum cascade laser (QCL) as a radiation source. This QCL contains aheterogeneous active region, which may be switched between single-mode emissions at 3.05,3.21, 3.28 and 3.35THz by adjusting the bias voltage.

Spectroscopic diffuse-reflection imaging at a 1.5 m stand-off distance, using a frequency-switchable terahertz quantum cascade laser

https://eprints.whiterose.ac.uk/88245/1/abstract.pdf

Spectroscopic diffuse-reflection imaging at a 1.5 m stand-off distance, using a frequency-switchable terahertz quantum cascade laser

Abstract

Similar works

Full text

Available Versions

White Rose Research Online