High-Efficiency Mini-Slab Laser Based on Tm-doped Double Tungstate Crystal

We report on highly-efficient room-temperature lasing in 5at.%Tm:KLu(WO4)2 mini-slabs side-pumped by a 35W diode bar. QCW (duty cycle ∼ 14%) output power of 1.47 W at 1908 nm has been demonstrated with optical and slope efficiencies being of 33 and 43% respectively. In our experiments, we used samples of active elements produced in the slabs form with Brewster’s angle cut faces and original laser cavity design.

Synthesis of monoclinic Ho,Tm:KLu(WO4)2 microrods with high photothermal conversion efficiency via thermal decomposition-assisted method

Monoclinic potassium lutetium double tungstate (KLu(WO4)2) microcrystals with precise rod shape were synthesized using a novel thermal decomposition-assisted method. The formation of the monoclinic crystalline phase was confirmed by X-ray...

In-Band Pumped Continuous-Wave Lasers Based on Ho:KY(WO4)2 Crystal and Ho:KGdYbY(WO4)2 Epitaxial Layer

2 μm lasers are in demand for a number of practical applications, such as environmental monitoring, remote sensing, medicine, material processing, and are also used as a pump sources for optical parametric generators. Crystals of double potassium tungstates doped with ions of rare-earth elements were shown to be promising materials both for the creation of classical solid-state lasers and waveguide lasers. The aim of this work was to develop a tunable pump laser in the spectral region of 1.9 µm based on double tungstate crystals doped with thulium ions and to study the lasing characteristics of a Ho:KY(WO4)2 crystal and a Ho:KGdYbY(WO4)2 single-crystal epitaxial layer under in-band pumping.With a Ho(1at.%):KY(WO4)2 crystal, continuous wave low-threshold lasing with an output power of 85 mW with a slope efficiency of 54 % at 2074 nm was achieved. For the first time to our knowledge, continuous wave laser generation in a waveguide configuration is realized in a single-crystal layer of potassium tungstate doped with holmium ions grown by liquid-phase epitaxy. The maximum output power at a wavelength of 2055 nm was 16.5 mW.

Microwave-assisted solid-state synthesis of NaRE(MO4)2 phosphors (RE = La, Pr, Eu, Dy; M = Mo, W)

Microwave heating provides rapid access to crystalline and phase pure double molybdate and double tungstate phosphors activated by rare-earth metal ions.

Lapping and Polishing of Crystalline KY(WO4)2: Toward High Refractive Index Contrast Slab Waveguides

Rare-earth ion-doped potassium yttrium double tungstate, RE:KY(WO4)2, is a promising candidate for small, power-efficient, on-chip lasers and amplifiers. Thin KY(WO4)2-on-glass layers with thicknesses ranging between 0.9 and 1.6 μm are required to realize on-chip lasers based on high refractive index contrast waveguides operating between 1.55 and 3.00 µm. The crystalline nature of KY(WO4)2 makes the growth of thin, defect-free layers on amorphous glass substrates impossible. Heterogeneous integration is one of the promising approaches to achieve thin KY(WO4)2-on-glass layers. In this process, crystal samples, with a thickness of 1 mm, are bonded onto a glass substrate and thinned down with an extensive lapping and polishing procedure to the desired final thickness. In this study, a lapping and polishing process for KY(WO4)2 was developed toward the realization of integrated active optical devices in this material.