A pulsed terahertz imaging system modified to perform angular detection of light for quantitatively characterizing reflection and scattering from samples is reported. Reflection from a gold mirror shows that the full width half maximum (FWHM) of the terahertz beam angular spread is <1° with signal-to-noise of 65 dB. Two samples, a paper index card and a corduroy cloth sample were tested. The index card reflects ca. 1% of the incident terahertz energy with similar angular spreading while the corduroy sample reflected approximately 0.01% of the incident terahertz energy with FWHM of 5-10°. The corduroy sample also exhibits temporal pulse scattering as a function of angle which correlates with direct frequency domain measurements.
Proceedings Title: Paper 8022-14, Session: "Passive Milllimeter Wave Imaging Technology XIV"
Conference Dates: April 24-29, 2011
Conference Location: Orlando, FL
Conference Title: SPIE Defense, Security & Sensing
Pub Type: Conferences
BRDF, concealed threat detection, terahertz reflection and scattering, terahertz imaging