Alberucci Alessandro, Laudyn Urszula A, Piccardi Armando, Kwasny Michał, Klus Bartlomiej, Karpierz Mirosław A, Assanto Gaetano
Photonics Laboratory, Tampere University of Technology, FI-33101 Tampere, Finland.
Faculty of Physics, Warsaw University of Technology, PL-00662 Warsaw, Poland.
Phys Rev E. 2017 Jul;96(1-1):012703. doi: 10.1103/PhysRevE.96.012703. Epub 2017 Jul 11.
We investigate nonlinear optical propagation of continuous-wave (CW) beams in bulk nematic liquid crystals. We thoroughly analyze the competing roles of reorientational and thermal nonlinearity with reference to self-focusing/defocusing and, eventually, the formation of nonlinear diffraction-free wavepackets, the so-called spatial optical solitons. To this extent we refer to dye-doped nematic liquid crystals in planar cells excited by a single CW beam in the highly nonlocal limit. To adjust the relative weight between the two nonlinear responses, we employ two distinct wavelengths, inside and outside the absorption band of the dye, respectively. Different concentrations of the dye are considered in order to enhance the thermal effect. The theoretical analysis is complemented by numerical simulations in the highly nonlocal approximation based on a semi-analytic approach. Theoretical results are finally compared to experimental results in the Nematic Liquid Crystals (NLC) 4-trans-4'-n-hexylcyclohexylisothiocyanatobenzene (6CHBT) doped with Sudan Blue dye.
我们研究了连续波（CW）光束在块状向列型液晶中的非线性光学传播。我们参照自聚焦/散焦现象，深入分析了取向和热非线性的竞争作用，并最终分析了非线性无衍射波包（即所谓的空间光孤子）的形成。在此范围内，我们研究了在高度非局域极限下由单束连续波光束激发的平面单元中掺杂染料的向列型液晶。为了调整两种非线性响应之间的相对权重，我们分别采用了染料吸收带内外的两个不同波长。考虑了不同浓度的染料以增强热效应。基于半解析方法的高度非局域近似下的数值模拟对理论分析进行了补充。理论结果最终与掺杂苏丹蓝染料的向列型液晶（NLC）4-反式-4'-正己基环己基异硫氰酸苯酯（6CHBT）的实验结果进行了比较。
