title: Mirrorless buried waveguide laser in monoclinic double tungstates fabricated by a novel combination of ion milling and liquid phase epitaxy.
abstract: Buried channel waveguides were fabricated by liquid phase epitaxial growth of a lattice-matched KY(0.58)Gd(0.22)Lu(0.17)Tm(0.03)(WO4)2 film on a microstructured KY(WO4)2 substrate. Channels were transferred to the substrates by standard photolithography and Ar-ion milling. The bottom and sidewalls of the milled channels were smooth enough (rms roughness = 70 nm and 20 nm, respectively) to favour the epitaxial growth of the active layer without defects at the boundary of substrate/epitaxial layer. The refractive index contrast was sufficient to enable light confinement and guided modes with low scattering losses were observed at wavelengths between 1440 nm and 1640 nm. CW laser operation at 1840 nm at room temperature was observed with feedback provided only by Fresnel reflection at the end faces, with slope efficiencies of 4% and 9% for TE and TM polarizations, respectively.
authors.affiliation: Física i Cristallografía de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili (URV), Tarragona, Spain.
authors.forename: Western
authors.initials: W
authors.lastname: Bolaños
authors.forename: Joan J
authors.initials: JJ
authors.lastname: Carvajal
authors.forename: Xavier
authors.initials: X
authors.lastname: Mateos
authors.forename: Ganapathy Senthil
authors.initials: GS
authors.lastname: Murugan
authors.forename: Ananth Z
authors.initials: AZ
authors.lastname: Subramanian
authors.forename: James S
authors.initials: JS
authors.lastname: Wilkinson
authors.forename: Eugenio
authors.initials: E
authors.lastname: Cantelar
authors.forename: Daniel
authors.initials: D
authors.lastname: Jaque
authors.forename: Ginés
authors.initials: G
authors.lastname: Lifante
authors.forename: Magdalena
authors.initials: M
authors.lastname: Aguiló
authors.forename: Francisco
authors.initials: F
authors.lastname: Díaz
mesh_terms: D003460:Crystallization / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D007834:Lasers; D007909:Lenses; D044367:Phase Transition; D012031:Refractometry / Q000295:instrumentation*; D017973:Tungsten Compounds / Q000138:chemical synthesis*
chemical_list: D007477:Ions; D017973:Tungsten Compounds; C045951:tungstate