Laser radiation absorption mediated hydrodynamic flux provides the strongest mechanism of optically induced reorientation of nematic liquid crystal (NLC). The thermal expansion, resulting from absorption induced heating, causes inhomogeneous flow of the NLC in the capillary which, due to the strong coupling of hydrodynamic and orientational degrees of freedom, leads to NLC reorientation. Laser induced hydrodynamic reorientations in homeotropic and hybrid oriented NLC have been studied theoretically and experimentally. In the case of homeotropic initial orientation of NLC molecules the velocity gradient induces a curvature of director. In the case of hybrid initial orientation of NLC velocity gradient brings about a small increase in curvature when the hydrodynamic flow velocity is directed out of the “flexible ribbon’s” curvature. The “flexible ribbon” reverses its curvature when velocity is directed into “flexible ribbon’s” curvature. This effect may allow detection of infrared radiation at a microwatt level.
May 19, 2021
Feb 27, 2020
|VOLUME EXPANSION MECHANISM OF LASER-INDUCED HYDRODYNAMIC REORIENTATION||May 19, 2021|
M. R. Hakobyan R. B. Alaverdyan R. S. Hakobyan Yu. S. Chilingaryan
Abrahamyan, A. S. Mkrtchyan, A. H. Chilingaryan, R. Yu. Hakobyan, A. S.
A. S. Abrahamyan R. Yu. Chilingaryan
V. V. Harutyunyan E. M. Aleksanyan V. C. Baghdasaryan P. B. Kostanyan G. Bondarenko M. Kirm S. Vielhauer
V. V. Sahakyan A. A. Sargsyan G. Zanyan T. S. Vardanyan B. A. Grigoryan V. M. Tsakanov
H. V. Baghdasaryan T. M. Knyazyan T. T. Hovhannisyan A. V. Daryan M. Marciniak
H. G. Julfayan