Nonlinear Optical Crystals: A Complete Survey

The development of nonlinear optical (NLO) borate crystals for generation of visible and UV light is reviewed. We first discussed on the basic principles of laser frequency conversion. Then, we examine the trends in research on NLO crystals. The background and present status of NLO borate crystals are summarized. The main considerations are focused on the discussion of crystals like CsLiB6O10 (CLBO), GdxY1−xCa4O(BO3)3 (GdYCOB) and K2Al2B2O7 (KAB). Properties of related materials like β-BaB2O2 (BBO), LiB3O5 (LBO), KBe2BO3F2 (KBBF), Sr2Be2BO7 (SBBO), CsB3O5 (CBO), GdCa4O(BO3)3 (GdCOB) and YCa4O(BO3)3 (YCOB) are included for comparison. We aim to provide a complete view of developing a new NLO borate material for actual laser applications. This review covers various aspects including the search for new materials, the growth of bulk crystals, the characterization of crystal properties as well as the development of new techniques to overcome obstacles in actual laser application, namely, thermal dephasing and laser-induced damage. Finally, perspectives on NLO borate crystals and all-solid-state UV lasers are evaluated.

Recent development of nonlinear optical borate crystals: key materials for generation of visible and UV light

Highly correlated photons or, accordingly, high-fidelity single-photon states are a prerequisite for closing detection loopholes in experimental tests of local realism and implementing scalable linear optical quantum computation. We demonstrate a parametric down-conversion source exhibiting a conditional detection efficiency of 51% (with corresponding preparation efficiency of 85%) and extraordinarily high detection rates of up to 8.5 x 10(5) coincidences/(s mW). We exploit a novel type-II phase matching configuration in a microstructured waveguide in conjunction with an ultrashort pump.

Efficient conditional preparation of high-fidelity single photon states for fiber-optic quantum networks.

Experimental and theoretical studies of the linear and nonlinear optical susceptibilities for single crystals of potassium titanyl phosphate KTiOPO4 are reported The state-of-the-art full potentia

Investigation of the linear and nonlinear optical susceptibilities of KTiOPO4 single crystals: theory and experiment.

https://hal.archives-ouvertes.fr/hal-00002488/document

75%-Efficiency blue generation from an intracavity PPKTP frequency doubler

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.

Optical studies of laser-induced gray-tracking in KTP

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

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

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.

Phase-matching measurements and Sellmeier equations over the complete transparency range of KTiOAsO 4 , RbTiOAsO 4 , and CsTiOAsO 4

We develop a methodology for the measurement of quadratic nonlinear optical properties of crystals. Our methods are mainly based on the use of the spherical geometry which allows, with only one crystal, accurate measurements of the phase-matching directions and the associated angular acceptances, double-refraction angles and effective coefficients. These data constitute a reliable basis for the modelling of the second-order electric susceptibility of crystals and for the comparison between materials.

Methodology for optical studies of nonlinear crystals: application to the isomorph family , , and

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 KTiOPO4 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 profile account well for our experimental results.

J.P. Feve

Papers

Optical studies of laser-induced gray-tracking in KTP

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

Phase-matching measurements and Sellmeier equations over the complete transparency range of KTiOAsO 4 , RbTiOAsO 4 , and CsTiOAsO 4

Methodology for optical studies of nonlinear crystals: application to the isomorph family , , and

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