title: Frequency and phase-lock control of a 3 THz quantum cascade laser.
abstract: We have locked the frequency of a 3 THz quantum cascade laser (QCL) to that of a far-infrared gas laser with a tunable microwave offset frequency. The locked QCL line shape is essentially Gaussian, with linewidths of 65 and 141 kHz at the -3 and -10 dB levels, respectively. The lock condition can be maintained indefinitely, without requiring temperature or bias current regulation of the QCL other than that provided by the lock error signal. The result demonstrates that a terahertz QCL can be frequency controlled with 1-part-in-10(8) accuracy, which is a factor of 100 better than that needed for a local oscillator in a heterodyne receiver for atmospheric and astronomic spectroscopy.
authors.affiliation: Center for Astrophysics and Space Astronomy, UCB 593, University of Colorado, Boulder, Boulder, Colorado 80309, USA. betz@colorado.edu
authors.forename: A L
authors.initials: AL
authors.lastname: Betz
authors.forename: R T
authors.initials: RT
authors.lastname: Boreiko
authors.forename: B S
authors.initials: BS
authors.lastname: Williams
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: Q
authors.initials: Q
authors.lastname: Hu
authors.forename: J L
authors.initials: JL
authors.lastname: Reno