title: Methodology for materials analysis using swept-frequency feedback interferometry with terahertz frequency quantum cascade lasers.
abstract: Recently, we demonstrated an interferometric materials analysis scheme at terahertz frequencies based on the self-mixing effect in terahertz quantum cascade lasers. Here, we examine the impact of variations in laser operating parameters, target characteristics, laser-target system properties, and the quality calibration standards on our scheme. We show that our coherent scheme is intrinsically most sensitive to fluctuations in interferometric phase, arising primarily from variations in external cavity length. Moreover we demonstrate that the smallest experimental uncertainties in the determination of extinction coefficients are expected for lossy materials.
authors.forename: Thomas
authors.initials: T
authors.lastname: Taimre
authors.forename: Karl
authors.initials: K
authors.lastname: Bertling
authors.forename: Yah Leng
authors.initials: YL
authors.lastname: Lim
authors.forename: Paul
authors.initials: P
authors.lastname: Dean
authors.forename: Dragan
authors.initials: D
authors.lastname: Indjin
authors.forename: Aleksandar D
authors.initials: AD
authors.lastname: Rakić