RESUMO
We report on the first deep-red laser operation of a heavily Eu3+-doped cesium gadolinium double molybdate crystal with a perfect cleavage. A 17 at. % Eu:CsGd(MoO4)2 laser based on cleaved single-crystal plates generated a maximum continuous-wave output power of 212â mW at 703.1â nm (5D0 â 7F4 transition) with a slope efficiency of 30.1%, a low laser threshold of 51â mW, linear polarization, and a beam quality factor M2 = 1.6-1.7. This monoclinic crystal is promising for deep-red microchip lasers.
RESUMO
We report on the crystal growth, spectroscopy and first laser operation of a novel double molybdate compound - Tm:KY(MoO4)2. This orthorhombic (sp. gr. Pbna) crystal exhibits strong anisotropy of the spectroscopic properties due to its layered structure. The maximum stimulated emission cross-section for the 3F4 â 3H6 transition is 2.70×10-20 cm2 at 1856nm with a bandwidth of >110â nm (for E || b). The lifetime of the 3F4 state is 2.29â ms. Crystalline films and plates (thickness down to 70 µm) of high optical quality are obtained by mechanical cleavage along the (100) plane. Continuous-wave diode-pumped laser operation is achieved in such thin films and plates yielding a maximum output power of 0.88 W at â¼1.9 µm with a slope efficiency of 65.8% and a linearly polarized laser output. Vibronic lasing is demonstrated at â¼2.06 µm. Tm:KY(MoO4)2 is promising for microchip and thin-disk lasers.
RESUMO
An investigation of Tm-Ho energy transfer in Tm(5at.%),Ho(0.4at.%):KYW single crystal by two independent techiques was performed. Based on fluorescence dynamics measurements, energy transfer parameters P71 and P28 for direct (TmâHo) and back (HoâTm) transfers, respectively, as well as equilibrium constant Θ were evaluated. The obtained results were supported by calculation of microscopic interaction parameters according to the Förster-Dexter theory for a dipole-dipole interaction. Diode-pumped continuous-wave operation of Tm,Ho:KYW microchip laser was demonstrated, for the first time to our knowledge. Maximum output power of 77 mW at 2070 nm was achieved at the fundamental TEM00 mode.
RESUMO
Thermo-optic coefficients anisotropy was characterized in monoclinic potassium (rare-earth) double tungstates KGd(WO4)2 and KY(WO4)2 in the spectral range of 0.44-0.63 µm by a modified minimum deviation method. This approach takes into account the changes in the shape and dimensions of the prismatic sample caused by the anisotropic thermal expansion effect under uniform heating together with the conventional measurements of minimum deviation angle. At room temperature at the wavelength of 633 nm, principal refractive indices for KGdW are n(p)=2.0135, n(m)=2.0458, and n(g)=2.0860, and for KYW they are n(p)=1.9979, n(m)=2.0396, and n(g)=2.0869. Optical axes position for KGdW (KYW) crystals is N(g) ± 42.60 (N(g) ± 44.1°) in the N(p)-N(g) plane. For both crystals, all the thermo-optic coefficients are negative and equal dn(p)/dT=-10.6, dn(m)/dT=-8.4, and dn(g)/dT=-15.2 for KGdW, and dn(p)/dT=-10.1, dn(m)/dT=-7.3, and dn(g)/dT=-8.4 for KYW [10(-6) K(-1)] (at 633 nm).
RESUMO
We measured the thermo-optic coefficients dn/dT of anisotropic Nd:KGd(WO(4))(2) crystals at the wavelengths of 1.064 µm and 532 nm (300 K) by a beam deflection method. The values of dn/dT are determined to be dn(p)/dT = -16.0 × 10(-6) K(-1), dn(m)/dT = -11.8 × 10(-6) K(-1), and dn(g)/dT = -19.5 × 10(-6) K(-1) (at 1.064 µm) and dn(p)/dT = -14.3 × 10(-6) K(-1), dn(m)/dT = -10.0 × 10(-6) K(-1), and dn(g)/dT = -15.0 × 10(-6) K(-1) (at 532 nm). Thermal lensing in the flashlamp-pumped N(p)- and N(g)-cut Nd:KGd(WO(4))(2) laser rods was studied at 1.064 µm by a probe beam technique in the nonlasing conditions, and the contribution of the photoelastic term to the thermal lens optical power was estimated. Athermal propagation directions with the definitions dn/dT + (n-1)α(T) = 0 and dn/dT + nα(T) = 0 were found in Nd:KGd(WO(4))(2).