High intensity behavior of pyroelectric photorefractive self-focusing in LiNbO3

Abstract

The formation of self-confined beams using pyroelectric effect is numerically and experimentally studied in photorefractive LiNbO 3 . For a given crystal temperature change, the trapped beam width is shown to be less efficient as intensity is increased. Numerical calculations reveal that the induced refractive-index profile varies along propagation for large intensities due to a nonlinear photovoltaic effect. Moreover, it eventually gives beam splitting for intensities greater than a threshold intensity that depends on LiNbO 3 composition.

Suppression of optical damage at 532 nm in Holmium doped congruent lithium niobate

“…Finally, the time dependent behavior of the transmitted intensity of Sample 4 suggests the possibility of secondary optical damage recovery mechanisms assisting in the optical damage suppression. These mechanisms are found in recent reports of pyroelectric spatial solitons [31,32], suppression of PR damage with a steady state temperature gradient [33], and observation of self-compensation of optical damage in chemically reduced LN [16]. At low intensity regimes, where laser-induced heating is negligible, optical damage was assumed to originate primarily due to the bulk photovoltaic effect.…”

Optofluidic platform using liquid crystals in lithium niobate microchannel

“…Such a field depends on the temperature variation according to the relation 20 :where p is the pyroelectric coefficient of the material. This parameter depends on the variation of spontaneous polarization with temperature and for congruent LiNbO 3 crystals is p ≅ (8 × 10 −5 ) C/m 2 °C 21 . Specifically, heating due to light absorption is known to produce the so called secondary pyroelectricity 22 , an effect where the polarization is induced piezoelectrically due to the temperature induced stress and deformations of the crystal.…”

Multihump thermo-reorientational solitary waves in nematic liquid crystals: Modulation theory solutions

“…More work along this path is forthcoming towards investigating two-dimensional self-localized beam solutions with additional azimuthal features and their stability in symmetric, as well as non-symmetric, configurations. The theoretical tools developed hereby are expected to play an important role in analyzing other self-localized structured beams stemming from opposite/competing nonlinear responses in NLC, as well as, e. g., metal nanoparticle suspensions [49], photorefractive crystals [50], ferroelectric/photovoltaic crystals with counteracting photocurrents [51,52], non-centrosymmetric crystals with a quadratic response [53], atomic vapours [54] and metamaterials [55], to mention only a few. thermo-reorientational nematicons are + 8γαβw…”