Thermo-optical parameters measured in ytterbium-doped potassium gadolinium tungstate.
ABSTRACT Oriented absorption and fluorescence spectra, refractive indices, thermal expansion, and thermal conductivities are reported for the anisotropic laser material ytterbium-doped potassium gadolinium tungstate, Yb3+:KGd(WO4)2. Measurements of negative values for dn/dT lead to the report of several useful athermal orientations for laser propagation.
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ABSTRACT: We investigated a diode-pumped multipass disk Yb:KGW amplifier intended for amplifying a train of 3D ellipsoidal pulses of a laser driver for a photocathode of a linear electron accelerator. The multipass amplification geometry permitted increasing the energy of broadband (about 10 nm) pulses with a repetition rate of 1 MHz from 0.12 µJ to 39 µJ, despite large losses (two orders of magnitude) introduced by a beam shaper of 3D ellipsoidal beam. The distortions of the pulse train envelope were minimal due to optimal delay between the moment of pump switching on and arrival of the first pulse of the train.Optics Express 04/2015; 23(8). DOI:10.1364/OE.23.009627 · 3.53 Impact Factor
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ABSTRACT: Principal thermo-optic coefficients, dn o/dT and dn e/dT, are determined for 7at.%Yb: YAl3(BO3)4 crystal by the use of a minimum deviation method, modified for anisotropic, optically uniaxial crystals. Direct measurements are accompanied by modeling of the dn/dT versus light wavelength dependence, yielding analytic thermo-optic dispersion formulae for the spectral range of 0.4–1.6 μm. At the wavelength of 1030 nm, dn o/dT = 3.5 and dn e/dT = 6.0 [10−6 K−1]. Sellmeier formulas are evaluated for the principal refractive indices n o and n e. The thermal coefficients of the optical path are determined for the principal crystal cuts of Yb:YAl3(BO3)4, a-cut and c-cut, and light polarizations, π or σ. Finally, thermal lens parameters are evaluated for Yb:YAl3(BO3)4 crystals on the basis of measured material parameters.Applied Physics B 11/2014; 117(2). DOI:10.1007/s00340-014-5870-6 · 1.63 Impact Factor