Conical light scattering in strontium barium niobate crystals related to an intrinsic composition inhomogeneity

Abstract

Conical light scattering is uncovered in poly- and mono-domain, nominally pure and Eu-doped strontium barium niobate (SBN) crystals over a wide temperature regime. The appearance of two scattering cones, a scattering line and a corona is observed and can be explained comprehensively within the Ewald sphere concept. Photorefraction, scattering from domain boundaries or from growth striations can be excluded from explaining the origin of the scattering. It is shown that the temperature-persistent scattering process is related to a growth-induced seeding rod, i.e. a composition inhomogeneity primarily localized at the centre of the SBN sample. The rod is directed parallel to the c axis and yields a refractive-index inhomogeneity with spatial frequencies on the micro-scale.

Three-Dimensional Spatiotemporal Pulse-Train Solitons

“…When the photorefractive nonlinearity is off (zero applied voltage), the beam diffracts significantly after propagating along 15 mm in the SBN crystal [ Fig. 2(b)] and reaches a size of FWHM ≈ 278 μm (the observed modulation in the diffracted beam is due to growth-induced "striations" in the crystal [41]). When applying a high voltage (500 V) on the SBN crystal, a spatial self-trapping is achieved [36][37][38].…”

Large acceptance of non-collinear phase-matching second harmonic generation on the surface of an anomalous-like bulk dispersion medium

“…Besides, there are some other types of phasematching approaches. For example, nonlinear Cherenkov radiation [5][6][7][8] with only the longitudinal phase-matching condition being satisfied, and conical second harmonic wave which is generated by the incident wave and its own scattering wave in a χ 2 photonic crystal [9][10][11][12][13]. Recent, we propose a surface complete phase-matching method [14][15][16] which utilizes sumfrequency wave generated by incident and reflected wave on the boundary of nonlinear crystal through non-collinear phase-matching process in anomalous-dispersion-like environment [17].…”

Conical sum-frequency generation in a bulk anomalous-like dispersion medium

“…The scattering is ascribed to the interaction of the incident light with a refractive-index inhomogeneity on the micro-scale in the bulk crystal. Besides the imperfections on the surface and inside the crystal, impurity ions are the most important scattering sources [20,21] . Thus, the phase-matching relationship could be realized as…”