Efficient 1.9µm monolithic Tm3+:NaLa(MoO4)2 micro-laser

Abstract

Efficient 1.9 µm monolithic micro‐laser was realized in a 0.9‐mm‐thick Tm3+:NaLa(MoO4)2 microchip coated with cavity mirrors directly. End‐pumped by a fiber‐coupled quasi‐continuous‐wave 795 nm diode laser, an average output power of 140 mW was obtained when the average incident pump power was 340 mW. Slope efficiencies calculated with respect to incident and absorbed pump power were 42 and 60%, respectively. The spectra and spatial profiles of the monolithic Tm3+:NaLa(MoO4)2 micro‐laser were also measured and analyzed. (© 2012 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)

Cation Ordering and Flexibility of the BO42– Tetrahedra in Incommensurately Modulated CaEu2(BO4)4 (B = Mo, W) Scheelites

“…Scheelite (CaWO 4 ) related compounds (A′,A″) n (BO 4 ) m with B = W and/or Mo are promising materials for phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. − Scheelites can be prepared with a large concentration of vacancies in the A sublattice, yielding compositions characterized by an A:B ratio different from 1:1. The creation of cation vacancies in the scheelite-type framework and the ordering of the A-cations and vacancies are a new factor in controlling the scheelite-type structure and properties. , Very often the population of the A-sites in the scheelite-type structure by cations with different sizes and charges (such as alkali metal cations M + and rare-earth cations R 3+ ) and/or cation vacancies leads to modulated structures with a pronounced occupational modulation wave. ,− …”

Efficient infrared (≈1.9–2.0 μm) laser operation in color-defect-free Tm:NaGd(MoO4)2crystal

“…For 7.5 at.% Tm:NaLa(MoO 4 ) 2 , approximately 500 mW of output laser power was obtained at λ ≈ 1900-2000 nm in the quasi-continuous wave (q-cw) regime with a slope efficiency of η = 50% (for T OC = 6.6%), but a pumping duty cycle as small as 5% was used [12], and up to approximately 400 mW in the continuous wave (cw) [13] regime with η = 53% (for T OC = 7.2%). A similar efficiency, but with lower output power (<140 mW) has been demonstrated through diode laser pumping of a microchip laser of this crystal [14]. The results obtained for 4.6 at.% Tm:NaGd(MoO 4 ) 2 air-annealed Cz-grown crystal are significantly worse: less than 200 mW with η = 25% (for T OC = 6.6%) was obtained in the q-cw regime (duty cycle 5%) [15].…”

KTb(MoO4)2 Green Phosphor with K+-Ion Conductivity: Derived from Different Synthesis Routes

“…The Mo- and W-based phosphors doped with rare earth elements are potential materials for pc-WLED applications (and also for solid-state lasers) due to opportunity to tailor the luminescence spectral characteristics and their excellent thermal stability. − In the near-UV region, they show strong absorption bands due to charge transfer from oxygen to Mo or W. Different methods can be used to produce Mo- and W-based phosphors doped by rare earth elements, including solid-state, − sol-combustion, , sol–gel, ,− and hydrothermal − methods. However, an important feature of these compounds is that bulk single crystals can be grown by the Czochralski technique. − ,− This makes it possible to measure many physical properties of compounds directly on single crystals and compare them with properties in the powder or ceramic forms. The luminescent properties strongly depend on their crystal structure, , preparation method, sintering temperature, − grain diameter, ,,, crystal size, and morphology. , …”