title: Femtosecond-laser-written Tm:KLu(WO4)2waveguide lasers.
abstract: Depressed-index channel waveguides with a circular and photonic crystal cladding structures are prepared in a bulk monoclinic Tm:KLu(WO4)2crystal by 3D direct femtosecond laser writing. The channel waveguide structures are characterized and laser operation is achieved using external mirrors. In the continuous-wave mode, the maximum output power of 46 mW is achieved at 1912 nm corresponding to a slope efficiency of 15.2% and a laser threshold of only 21 mW. Passive Q-switching of a waveguide with a circular cladding is realized using single-walled carbon nanotubes. Stable 7 nJ/50 ns pulses are achieved at a repetition rate of 1.48 MHz. This first demonstration of ∼2  μm fs-laser-written waveguide lasers based on monoclinic double tungstates is promising for further lasers of this type doped with Tm3+and Ho3+ions.
authors.forename: Esrom
authors.initials: E
authors.lastname: Kifle
authors.forename: Xavier
authors.initials: X
authors.lastname: Mateos
authors.forename: Javier Rodríguez Vázquez
authors.initials: JR
authors.lastname: de Aldana
authors.forename: Airan
authors.initials: A
authors.lastname: Ródenas
authors.forename: Pavel
authors.initials: P
authors.lastname: Loiko
authors.forename: Sun Yung
authors.initials: SY
authors.lastname: Choi
authors.forename: Fabian
authors.initials: F
authors.lastname: Rotermund
authors.forename: Uwe
authors.initials: U
authors.lastname: Griebner
authors.forename: Valentin
authors.initials: V
authors.lastname: Petrov
authors.forename: Magdalena
authors.initials: M
authors.lastname: Aguiló
authors.forename: Francesc
authors.initials: F
authors.lastname: Díaz