Refined Sellmeier equations from phase-matching measurements over the complete transparency range of KTiOAsO4, RbTiOAsO4 and CsTiOAsO4

2000

Sum- and difference- frequency generation phasematching properties are measured in spheres of KTiOAsO4, RbTiOAsO4 and CsTiOAsO4 for Sellmeier equations refinement over their complete transparency range.

Absolute measurement of quadratic nonlinearities from phase-matched second-harmonic generation in a single KTP crystal cut as a sphere

1997

We determine within an accuracy of ∼10% the absolute magnitude of the quadratic effective coefficients of types I and II phase-matched second-harmonic generation from conversion efficiency measurements in a single nonlinear crystal cut as a sphere. The agreement is good with measurements performed in thin parallelepipedal samples. The material studied is KTiOPO4, for which improved Sellmeier equations are given.

Phase-matching measurements and Sellmeier equations over the complete transparency range of KTiOAsO_4, RbTiOAsO_4, and CsTiOAsO_4

2000

The sphere method is used for the direct measurement of sum- and difference-frequency generation phase matched in the principal planes of KTiOAsO4, RbTiOAsO4, and CsTiOAsO4, including the tuning curves of 1.064-µm-pumped OPO’s emitting between 3 and 5 µm. The nonlinear least-squares fitting of our experimental data leads to refined dispersion equations of the principal refractive indices; the resulting dual-oscillator form equations are valid over the complete transparency range of the three studied materials.

Efficient energy conversion for cubic third-harmonic generation that is phase matched in KTiOPO(4).

2000

We demonstrate, for the first time to our knowledge, that efficient third-harmonic generation can be achieved with a cubic contribution much larger than the quadratic processes. An energy-conversion efficiency of 2.4% is achieved for cubic third-harmonic generation that is phase matched along the x axis of a KTiOPO(4) crystal by use of a picosecond fundamental laser emitting at 1618 nm. The associated cascading processes are only 10% of the pure cubic interaction, which is very suitable for study of the specific quantum optical correlations. Calculations of the third-harmonic generation conversion efficiency with respect to group-velocity dispersion and to the longitudinal Gaussian beam pro…

Crystal growth and refined Sellmeier equations over the complete transparency range of RbTiOPO4

2003

Abstract The phase-matching directions sum- and difference-frequency generations are measured in the principal planes of RbTiOPO 4 crystals grown from a halide flux. The use of crystals with a cylindrical shape and of a tunable laser source allows us to perform accurate measurements over the complete transparency range of that material, and to determine a refined set of Sellmeier equations valid for any phase-matched interaction in that crystal.

Optimized blue light generation in optically contacted walk-off compensated RbTiOAsO4 and KTiOP1−yAsyO4

1999

Abstract We study type II 1.32 μm second harmonic generation (SHG) in a RbTiOAsO 4 optically contacted walk-off compensated device. The reduction of the effective walk-off angle by a factor of 3.7 with respect to KTiOPO 4 for the same interaction leads to an enhancement by a factor of 10 of the conversion efficiency. A model is proposed for both type I and type II SHG in such a structure. The angular tuning curve is a multi-peaked one, as predicted by the model. The enhancement of the SHG conversion efficiency allows us to optimize the generation of blue laser light at 440 nm: a specially designed KTiOP 0.98 As 0.02 O 4 solid solution crystal achieves angular non-critical phase matching at …

Optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals

2007

International audience; We report a complete optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals. We studied the relative orientation between the dielectric and the crystallographic frames as a function of the wavelength and performed accurate phase-matching angles measurements for second harmonic generation, using a single crystal cut as a sphere. We also recorded polarized luminescence spectra of Nd:YCOB along the principal axes of the dielectric frame. For both crystals, we measured the gray-tracking and the thermo-optic properties as a function of temperature and wavelength using oriented slabs. Finally, we measured all their dielectric and electro-optic coefficients, as…

Cubic optical nonlinearity of

1999

We perform angular non-critical phase-matching third-harmonic generation (THG) experiments in (KTP). From these experiments, we determine the magnitude and sign of the two phase-matched nonlinear coefficients of by a complete analysis of phase-matching properties of the cascaded quadratic and pure cubic processes, the resolution of the coupled propagation equations and by the calculation of the quadratic and cubic dielectric susceptibility tensor by an extended bond charge model; we find: and . We also demonstrate that the two studied THG are mainly governed by the cubic interaction.

Optical studies of laser-induced gray-tracking in KTP

1999

We have studied gray-tracking induced by a pulsed and polarized 532-nm laser beam in flux grown KTiOPO/sub 4/ (KTP) crystals. Transmission spectra measured under polarized light give different results: gray-tracking leads to an increase in the initial anisotropy of the linear optical properties of KTP, and the polar axis is the most sensitive to this process. The dynamics of relaxation of gray-tracking is anisotropic and depends on the wavelength under analysis. We show a possible induced modification of the crystal surface and also the existence of an intensity above which gray-tracking reaches the saturation point. We then measure the temperature above which gray-tracking no longer exists.

Measurement and modelization of cubic nonlinearity in KTiOPO/sub 4/

2005

Non-critically phase-matched cascaded THG at 440 nm in KTiOP1−yAsyO4 crystals

1995

Abstract We report the relative nonlinear optical properties of flux-grown KTiOP 1− y As y O 4 crystals ( y =0, y =0.03 and y =0.12). The non-critical phase-matching temperatures along the x -axis for blue generation by type II indirect third harmonic generation from 1318.8 nm and 1320 nm are measured. The phosphorus-arsenic substitution allows a “chemical tuning” of the phase-matching properties, through a birefringence variation, so that non-critical phase-matching at room temperature is possible for the previous interactions. Type II frequency doubling from 1064 nm is briefly considered.