Laser Feedback Interferometry as a Tool for Analysis of Granular Materials at Terahertz Frequencies: Towards Imaging and Identification of Plastic Explosives
She Han,
Karl Bertling,
Paul Dean,
James Keeley,
Andrew D. Burnett,
Yah Leng Lim,
Suraj P. Khanna,
Alexander Valavanis,
Edmund H. Linfield,
A. Giles Davies,
Dragan Indjin,
Thomas Taimre,
Aleksandar D. Rakić
Affiliations
She Han
School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia
Karl Bertling
School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia
Paul Dean
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
James Keeley
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Andrew D. Burnett
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Yah Leng Lim
School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia
Suraj P. Khanna
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Alexander Valavanis
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Edmund H. Linfield
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
A. Giles Davies
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Dragan Indjin
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK
Thomas Taimre
School of Mathematics and Physics, The University of Queensland, Brisbane QLD 4072, Australia
Aleksandar D. Rakić
School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane QLD 4072, Australia
We propose a self-consistent method for the analysis of granular materials at terahertz (THz) frequencies using a quantum cascade laser. The method is designed for signals acquired from a laser feedback interferometer, and applied to non-contact reflection-mode sensing. Our technique is demonstrated using three plastic explosives, achieving good agreement with reference measurements obtained by THz time-domain spectroscopy in transmission geometry. The technique described in this study is readily scalable: replacing a single laser with a small laser array, with individual lasers operating at different frequencies will enable unambiguous identification of select materials. This paves the way towards non-contact, reflection-mode analysis and identification of granular materials at THz frequencies using quantum cascade lasers.
