TY - JOUR
T1 - Optimized frequency regime for the electrohydrodynamic induction of a uniformly lying helix structure
AU - Nian, Yu Lin
AU - Wu, Po Chang
AU - Lee, Wei
N1 - Publisher Copyright:
© 2016 Chinese Laser Press.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - This study specifies the optimal frequency regime for the uniformly lying helix (ULH) alignment induced by the electrohydrodynamic (EHD) effect in a cholesteric liquid crystal with positive dielectric anisotropy. Based on the transport behavior of ionic charges in response to the externally applied ac electric field, four frequency regimes, divided by three critical frequencies (i.e., fL, fR, and fH), are identified by means of dielectric spectroscopy. By discussing the voltage-dependent cholesteric textural changes in each frequency regime in terms of the voltageand frequency-dependent transmission spectra and optical textures, our results suggest that the designated frequency regime fL, R, where electrical charges can effectively oscillate in the bulk of the cell with less ion accumulation on the electrode surfaces, is most adequate for the generation of well-structured ULH via effective induction of the EHD flow by the external voltage. As a result, this study provides a pathway to determination of the optimal frequency regime for generating the EHD-induced ULH state prior to voltage treatment.
AB - This study specifies the optimal frequency regime for the uniformly lying helix (ULH) alignment induced by the electrohydrodynamic (EHD) effect in a cholesteric liquid crystal with positive dielectric anisotropy. Based on the transport behavior of ionic charges in response to the externally applied ac electric field, four frequency regimes, divided by three critical frequencies (i.e., fL, fR, and fH), are identified by means of dielectric spectroscopy. By discussing the voltage-dependent cholesteric textural changes in each frequency regime in terms of the voltageand frequency-dependent transmission spectra and optical textures, our results suggest that the designated frequency regime fL, R, where electrical charges can effectively oscillate in the bulk of the cell with less ion accumulation on the electrode surfaces, is most adequate for the generation of well-structured ULH via effective induction of the EHD flow by the external voltage. As a result, this study provides a pathway to determination of the optimal frequency regime for generating the EHD-induced ULH state prior to voltage treatment.
UR - http://www.scopus.com/inward/record.url?scp=85003671295&partnerID=8YFLogxK
U2 - 10.1364/PRJ.4.000227
DO - 10.1364/PRJ.4.000227
M3 - Article
AN - SCOPUS:85003671295
SN - 2327-9125
VL - 4
SP - 227
EP - 232
JO - Photonics Research
JF - Photonics Research
IS - 6
ER -