Bertrand Ménaert

Relative sign and absolute magnitude of d (2) nonlinear coefficients of KTP from second-harmonic-generation measurements

We determine the absolute magnitude of the dij(2) coefficients of KTP, using type-I and type-II phase-matching second-harmonic-generation efficiency measurements: |d15 (0.532 μm)| = 1.4 ± 0.07 pm/V, |d24 (0.532 μm)| = 2.65 ± 0.13 pm/V, and |d33 (0.532 μm)| = 10.7 ± 0.5 pm/V. We establish that these coefficients have the same sign. We compare the obtained magnitudes with the main previously published results.

Widely and continuously tunable optical parametric oscillator based on a cylindrical periodically poled KTiOPO 4 crystal

We report on what is to our knowledge the first realization of a quasi-phase-matched optical parametric oscillator (OPO) based on a crystal with a cylindrical shape. The main reason for interest in this device is its broad, continuous tuning. In experiments with a 1064-nm pump, the signal tuning range was equal to 525 nm (1515-2040 nm), and the corresponding idler was continuously tuned over 1340 nm (2220-3560 nm). The angular tuning was 26 degrees , with only a minor variation of the OPO threshold over the entire tuning range.

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

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.

Absorption and fluorescence anisotropies of monoclinic crystals : the case of Nd:YCOB

We report for the first time measurements and modelization of the angular distributions of absorption and fluorescence in a monoclinic crystal. Studies on Nd:YCOB revealed specific topologies with ombilics. These new data upgrade the knowledge on low symmetry crystal optics.

Linear and nonlinear optical properties of the monoclinic Ca 4 YO(BO 3 ) 3 crystal

We report that the optical frame orientation is wavelength independent over the entire transmission range of the nonlinear monoclinic crystal Ca4YO(BO3)3 (YCOB). We used a new method based on internal conical refraction associated with x-ray diffraction on a single crystal cut as a sphere. Direct phase-matching-angle measurements of second-harmonic generation were performed in the principal planes of the spherical crystal for fundamental wavelengths up to 3.5 μm, and three absorption peaks were measured above 2.4 μm. By fitting all data simultaneously, we found new dispersion equations of the refractive indices of YCOB.

Ferroelectric transition and melting temperatures of new compounds: CsTiOAsO4 and CsxM1-xTiOAsyP1-yO4 with M identical to K or Rb

The authors have synthesised, by the flux-growth method, millimetric crystals of new isotype compounds of KTiOPO4 which also have nonlinear optical properties: cesium titanyl arsenate CsTiOAsO4 and the complete or incomplete solid solutions of general formula CsxM1-xTiOAsyP1-yO4 with M identical to K or Rb. The second harmonic generation test (SHG:1.064 mu m/0.532 mu m) is positive for all these compounds. The ferroelectric transition temperatures are determined by measuring the temperatures at which the SHG disappears. The melting points of the compounds are also determined.

Continuous tuning of a microlaser-pumped optical parametric generator by use of a cylindrical periodically poled lithium niobate crystal

An optical parametric generator with a cylindrical periodically poled LiNbO3 crystal and a Nd:YAG commercial microchip pump laser yields continuous tuning of the emitted wavelengths over a broad spectral range (1.42-1.7 microm and 2.8-4.2 microm), with large efficiency, a high repetition rate, and low divergence, in a compact and stable device.

Widely tunable optical parametric oscillator in a 5 mm thick 5% MgO:PPLN partial cylinder

A 5 mm thick and 38 mm long 5% MgO-doped periodically poled lithium niobate (MgO:PPLN) cylinder with a grating period of 28 μm has been engineered as a partial cylinder with an angular aperture of 45°. An optical parametric oscillator based on this crystal and pumped at 1.064 μm is reported. The output energy is comparable to that generated in the same kind of sample cut as a slab, but the wavelength tunability from 1.41 to 4.3 μm is much broader and continuous.

Phase-matching properties and refined Sellmeier equations of the new nonlinear infrared crystal CdSiP2.

We directly measured the second harmonic generation and difference frequency generation phase-matching directions of the nonlinear crystal CdSiP(2) until 9.5 μm using the sphere method. The simultaneous fit of the experimental angular data allowed the Sellmeier equations of the ordinary and extraordinary principal refractive indices to be refined over the entire transparency range of the crystal.

Phase-matching directions, refined Sellmeier equations, and second-order nonlinear coefficient of the infrared Langatate crystal La 3 Ga 5.5 Ta 0.5 O 14

We directly measured phase-matching directions of second harmonic, sum, and difference frequency generations in the Langatate La₃Ga(5.5)Ta(0.5)O₁₄ (LGT) uniaxial crystal. The simultaneous fit of the data enabled us to refine the Sellmeier equations of the ordinary and extraordinary principal refractive indices over the entire transparency range of the crystal, and to calculate the phase-matching curves and efficiencies of LGT for infrared optical parametric generation.