Jampani V S R, Skarabot M, Takezoe H, Muševič I, Dhara S
J. Stefan Institute, Ljubljana, Slovenia.
Opt Express. 2013 Jan 14;21(1):724-9. doi: 10.1364/OE.21.000724.
We demonstrate laser-driven microflow-induced orientational change (homeotropic to planar) in a dye-doped nematic liquid crystal. The homeotropic to planar director alignment is achieved in unrubbed cells in the thermal hysteresis range of a discontinuous anchoring reorientation transition due to the local heating by light absorption in dye-doped sample. Various bistable patterns were recorded in the cell by a programmable laser tweezers. The width of the patterns depend on the scanning speed of the tightly focussed laser beam and the minimum width obtained is approximately equal to 0.57μm which is about 35 times smaller than the earlier report in the rubbed cells. We show that the motion of the microbeam spot causes local flow as a result the liquid crystal director is aligned along that direction.
我们展示了在掺杂染料的向列型液晶中由激光驱动的微流诱导的取向变化（垂直取向到平面取向）。由于掺杂染料样品中光吸收引起的局部加热，在不连续锚定重取向转变的热滞回范围内，未摩擦的液晶盒实现了垂直取向到平面取向的指向矢排列。通过可编程激光镊子在液晶盒中记录了各种双稳态图案。这些图案的宽度取决于紧密聚焦激光束的扫描速度，获得的最小宽度约为0.57μm，比之前在摩擦液晶盒中的报道小约35倍。我们表明，微光束光斑的移动会引起局部流动，结果液晶指向矢沿该方向排列。
