title: Mode-locking of a terahertz laser by direct phase synchronization.
abstract: A novel scheme to achieve mode-locking of a multimode laser is demonstrated. Traditional methods to produce ultrashort laser pulses are based on modulating the cavity gain or losses at the cavity roundtrip frequency, favoring the pulsed emission. Here, we rather directly act on the phases of the modes, resulting in constructive interference for the appropriated phase relationship. This was performed on a terahertz quantum cascade laser by multimode injection seeding with an external terahertz pulse, resulting in phase mode-locked terahertz laser pulses of 9 ps duration, characterized unambiguously in the time domain.
authors.affiliation: Laboratoire Pierre Aigrain, Ecole Normale Supérieure, CNRS (UMR 8551), Université P. et M. Curie, Université D. Diderot, 75231 Paris Cedex 05, France.
authors.forename: J
authors.initials: J
authors.lastname: Maysonnave
authors.forename: K
authors.initials: K
authors.lastname: Maussang
authors.forename: J R
authors.initials: JR
authors.lastname: Freeman
authors.forename: N
authors.initials: N
authors.lastname: Jukam
authors.forename: J
authors.initials: J
authors.lastname: Madéo
authors.forename: P
authors.initials: P
authors.lastname: Cavalié
authors.forename: R
authors.initials: R
authors.lastname: Rungsawang
authors.forename: S P
authors.initials: SP
authors.lastname: Khanna
authors.forename: E H
authors.initials: EH
authors.lastname: Linfield
authors.forename: A G
authors.initials: AG
authors.lastname: Davies
authors.forename: H E
authors.initials: HE
authors.lastname: Beere
authors.forename: D A
authors.initials: DA
authors.lastname: Ritchie
authors.forename: S S
authors.initials: SS
authors.lastname: Dhillon
authors.forename: J
authors.initials: J
authors.lastname: Tignon