Absorption-sensitive diffuse reflection imaging of concealed powders using a terahertz quantum cascade laser.
We report diffuse reflection imaging in air of concealed powdered samples using a terahertz quantum cascade laser. The sensitivity of the detection scheme to sub-surface absorption within samples is confirmed using fully-characterized powdered admixtures of polystyrene and polymethyl methacrylate (PMMA). Measurements of the backscattering intensity from these samples are then used in conjunction with Kubelka-Munk scattering theory, as well as several models based on the quasi-crystalline approximation, to extract the absorption coefficient of PMMA. Our research demonstrates the feasibility of high-resolution frequency-domain terahertz imaging for the detection and identification of concealed powders in a reflection geometry.
School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK. p.dean@leeds.ac.uk
Paul
P
Dean
Muhammad U
MU
Shaukat
Suraj P
SP
Khanna
Subhasish
S
Chakraborty
Mohammad
M
Lachab
Andrew
A
Burnett
Giles
G
Davies
Edmund H
EH
Linfield
D000042:Absorption; D003461:Crystallography; D004058:Diffusion; D021621:Imaging, Three-Dimensional; D054023:Lasers, Semiconductor; D008027:Light; D020959:Polyethylene / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011208:Powders / Q000032:analysis*; D012542:Scattering, Radiation
D011208:Powders; D020959:Polyethylene; D019904:Polymethyl Methacrylate