DocumentCode :
3185035
Title :
Amazing nonlinear optical response in thin unoriented nematic liquid crystal cells
Author :
Lucchetti, L. ; Di Fabrizio, M. ; Francescangeli, O. ; Simoni, F.
Author_Institution :
Dipt. di Fisica e Ingegneria dei Materiali e del Territorio, Ancona Univ., Italy
fYear :
2003
fDate :
22-27 June 2003
Firstpage :
61
Abstract :
This work reports the highest optical nonlinearity (to the best of the authors knowledge) ever observed. The samples showing this behaviour are unoriented methyl-red doped 5CB cells with thickness of 1-2 μ. Dynamic gratings are obtained with two cw coherent laser beams (λ = 532 nm) linearly polarised in the same direction, which impinge on the samples at normal incidence (i.e. the bisector of the crossing angle is parallel to the cell normal). The diffraction efficiency η = I+I/IO has been evaluated by means of a low power He-Ne probe beam. Diffraction efficiencies of the order of 20-30% are easily reachable with a total incident intensity of a few μm/cm2. By fitting the experimental data using the expression valid for thin gratings η = |J1(ξ)|2, values in the range (1250 - 1325) cm2/W can be obtained for the nonlinear coefficient n2. It is worth noting that the small thickness is a stringent condition for observing such an amazing nonlinear response.
Keywords :
diffraction gratings; measurement by laser beam; nematic liquid crystals; nonlinear optics; 532 nm; He-Ne probe beam; coherent laser beams; continuous wave laser beams; diffraction efficiency; dynamic gratings; linear polarisation; methyl-red doped 5CB cells; nematic liquid crystal cells; nonlinear coefficient; nonlinear optical response; optical nonlinearity; unoriented liquid crystal cells; Diffraction; Gratings; Laser beams; Liquid crystals; Nonlinear optics; Optical refraction; Optical variables control; Probes; Refractive index; Torque;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Quantum Electronics Conference, 2003. EQEC '03. European
Print_ISBN :
0-7803-7733-8
Type :
conf
DOI :
10.1109/EQEC.2003.1313918
Filename :
1313918
Link To Document :
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