TY - JOUR
T1 - A novel heterodyne polarimeter for the multiple-parameter measurements of twisted nematic liquid crystal cell using a genetic algorithm approach
AU - Yu, Tsung Chih
AU - Lo, Yu Lung
N1 - Funding Information:
Manuscript received September 18, 2006; revised December 11, 2006. This work was supported by the Chi-Mei Optoelectronics (CMO), Taiwan. The authors are with the Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan, R.O.C. (e-mail: [email protected]; [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JLT.2006.890452
PY - 2007/3
Y1 - 2007/3
N2 - A new method for measuring the multiple parameters of a twisted nematic liquid crystal (TNLC) by applying a genetic algorithm is presented. This paper adopts an electrooptic modulator to modulate the linear polarized light which passed through a TNLC cell in a heterodyne polarimetric setup. The intensity ratio and the phase of the detected heterodyne signal are used for the inverse calculation in the LC cell parameters by applying a genetic algorithm approach. As a result, the multiparameter measurements in the entrance director angle of TNLC, twist angle, and cell thickness are achieved. The advantage of the heterodyne polarimeter introduces high sensitivity on intensity and phase detections, and the multiple parameters could be easily extracted through the genetic algorithm. Also, the ambiguity in the angle extraction could be uniquely solved in this paper. The experimental results show that the average deviation of 0.01° and 0.013 μm in the measurement of twist angle and cell thickness, respectively, have been obtained. The average deviation of 0.23° in the measurement of director angle has also been achieved.
AB - A new method for measuring the multiple parameters of a twisted nematic liquid crystal (TNLC) by applying a genetic algorithm is presented. This paper adopts an electrooptic modulator to modulate the linear polarized light which passed through a TNLC cell in a heterodyne polarimetric setup. The intensity ratio and the phase of the detected heterodyne signal are used for the inverse calculation in the LC cell parameters by applying a genetic algorithm approach. As a result, the multiparameter measurements in the entrance director angle of TNLC, twist angle, and cell thickness are achieved. The advantage of the heterodyne polarimeter introduces high sensitivity on intensity and phase detections, and the multiple parameters could be easily extracted through the genetic algorithm. Also, the ambiguity in the angle extraction could be uniquely solved in this paper. The experimental results show that the average deviation of 0.01° and 0.013 μm in the measurement of twist angle and cell thickness, respectively, have been obtained. The average deviation of 0.23° in the measurement of director angle has also been achieved.
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U2 - 10.1109/JLT.2006.890452
DO - 10.1109/JLT.2006.890452
M3 - Article
AN - SCOPUS:34247165200
SN - 0733-8724
VL - 25
SP - 946
EP - 951
JO - Journal of Lightwave Technology
JF - Journal of Lightwave Technology
IS - 3
ER -