Waveguide lasers on monoclinic potassium double tungstates

Monoclinic potassium double tungstates KRE(WO4)2 (RE = Y, Gd, Lu) belonging to the C2/c space group have shown to be excellent laser hosts for active lanthanide ions due to the following advantages: (i) very high values of absorption and emission crosssections and (ii) relatively large ion separation allowing doping levels with minimum quenching effects. These characteristics, together with the refractive indices of around 2.0, that allows fabrication of compact integrated optical devices, make this family of materials attractive for integrated optics applications. The successful combination of the advantages of the waveguide laser geometry and the spectroscopic properties of monoclinic double tungstates was confirmed in this work by the realization of planar and channel waveguide lasers activated with Tm3+. Surface channel waveguides were fabricated by structuring the surface of the Er3+ and Tm3+-doped planar waveguides by means of standard UV-photolithography and Arion milling. On the other hand, this work proposes the fabrication of other optical devices such as microring resonators that may be used as filters or even as a mirrorless waveguide laser source.