title: Widely tunable quantum cascade laser-based terahertz source.
abstract: A compact, tunable, ultranarrowband terahertz source, Δν∼1  MHz, is demonstrated by upconversion of a 2.324 THz, free-running quantum cascade laser with a THz Schottky-diode-balanced mixer using a swept, synthesized microwave source to drive the nonlinearity. Continuously tunable radiation of 1 μW power is demonstrated in two frequency regions: ν(Laser) ± 0 to 50 GHz and ν(Laser) ± 70 to 115 GHz. The sideband spectra were characterized with a Fourier-transform spectrometer, and the radiation was tuned through CO, HDO, and D2O rotational transitions.
authors.forename: Andriy A
authors.initials: AA
authors.lastname: Danylov
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Light
authors.forename: Jerry
authors.initials: J
authors.lastname: Waldman
authors.forename: Neal
authors.initials: N
authors.lastname: Erickson
authors.forename: Xifeng
authors.initials: X
authors.lastname: Qian