title: Coherent phase lock of a 9 μm quantum cascade laser to a 2 μm thulium optical frequency comb.
abstract: We demonstrate coherent phase locking of a room-temperature continuous-wave quantum cascade laser (QCL) at 9.1 μm to a Tm-fiber laser frequency comb centered at 2 μm, with an integrated residual phase error of 0.9 rad (30 mHz to 1.5 MHz). This resulted in a QCL linewidth reduction from 525 to 25 kHz at 1 ms observation time, limited by the linewidth of the free-running frequency comb.
authors.affiliation: IMRA America Inc., 1044 Woodridge Avenue, Ann Arbor, Michigan 48105, USA. amills@imra.com
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Mills
authors.forename: Davide
authors.initials: D
authors.lastname: Gatti
authors.forename: Jie
authors.initials: J
authors.lastname: Jiang
authors.forename: Christian
authors.initials: C
authors.lastname: Mohr
authors.forename: Will
authors.initials: W
authors.lastname: Mefford
authors.forename: Livio
authors.initials: L
authors.lastname: Gianfrani
authors.forename: Martin
authors.initials: M
authors.lastname: Fermann
authors.forename: Ingmar
authors.initials: I
authors.lastname: Hartl
authors.forename: Marco
authors.initials: M
authors.lastname: Marangoni