TY - JOUR
T1 - Orientational photorefractive effect in undoped and CdSe nanorods-doped nematic liquid crystal - Bulk and interface contributions
AU - Khoo, Iam Choon
AU - Chen, Kan
AU - Williams, Yana Zhang
N1 - Funding Information:
Manuscript received July 9, 2005; revised January 12, 2006 and February 1, 2006. This work was supported by the Army Research Office, by the Air Force Office of Scientific Research, and by the National Science Foundation MRSEC Center for Nanoscale Science under Grant DMR-0213623. The authors are with the Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 USA (e-mail: [email protected]). Digital Object Identifier 10.1109/JSTQE.2006.871955
PY - 2006/5
Y1 - 2006/5
N2 - In the work, we revisited the orientational photorefractive effect generated in nematic liquid crystal (NLC) in a degenerate four-wave mixing interaction configuration. A detailed calculation of the bulk laser-induced space-charge fields and analytical expressions for the reorientation angles and the required dc threshold fields are obtained and compared with experimental measurements. While the bulk theory could describe the general features of the self-diffraction and threshold fields, there are significant deviations from experimental observation, particularly in an observed lowering of the threshold voltage by the optical intensity. This effect is due to an optically induced surface-charge modulation. A theoretical analysis including both the bulk and the surface-charge-modulation effects allows us to obtain better agreement with experimental observations of the threshold voltages on the optical intensity and sample thicknesses, and to estimate the relative contributions from the bulk and surface effects. Recently observed enhanced photorefractive effects of CdSe nanorods-doped NLCs are also reported to corroborate these analyses and to provide guidelines to optimize the photorefractive effect for dynamic holographic application.
AB - In the work, we revisited the orientational photorefractive effect generated in nematic liquid crystal (NLC) in a degenerate four-wave mixing interaction configuration. A detailed calculation of the bulk laser-induced space-charge fields and analytical expressions for the reorientation angles and the required dc threshold fields are obtained and compared with experimental measurements. While the bulk theory could describe the general features of the self-diffraction and threshold fields, there are significant deviations from experimental observation, particularly in an observed lowering of the threshold voltage by the optical intensity. This effect is due to an optically induced surface-charge modulation. A theoretical analysis including both the bulk and the surface-charge-modulation effects allows us to obtain better agreement with experimental observations of the threshold voltages on the optical intensity and sample thicknesses, and to estimate the relative contributions from the bulk and surface effects. Recently observed enhanced photorefractive effects of CdSe nanorods-doped NLCs are also reported to corroborate these analyses and to provide guidelines to optimize the photorefractive effect for dynamic holographic application.
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U2 - 10.1109/JSTQE.2006.871955
DO - 10.1109/JSTQE.2006.871955
M3 - Article
AN - SCOPUS:33745024074
SN - 1077-260X
VL - 12
SP - 443
EP - 450
JO - IEEE Journal on Selected Topics in Quantum Electronics
JF - IEEE Journal on Selected Topics in Quantum Electronics
IS - 3
ER -