Sensitive voltage-dependent diffraction of a liquid crystal Fresnel lens.
This investigation proposes a Fresnel liquid crystal (LC) lens with high diffraction efficiency and a low driving voltage. A Fresnel zone electrode was fabricated on a glass plate. A Fresnel zone-distributed electric field in the LC cell was induced by a proper driving voltage, yielding a concentric structure of LCs as a Fresnel phase lens. A remarkable diffraction efficiency of ~39%, close to the theoretical limit of 40.5%, was detected when the LC lens was probed using a polarized incident beam with a wavelength of 632.8 nm. The diffraction efficiency of the Fresnel LC lens was demonstrated to depend sensitively on the applied voltage. The most suitable driving voltage of the Fresnel LC lens was as low as 0.9 V. This study may support progress in the electrical modulation of the optical properties of various optical systems.
Hung
Wen-Chi
WC
Department of Physics, National Sun Yat-sen University, Kaohsiung 804, Taiwan, Republic of China.
Chen
Yu-Jen
YJ
Lin
Chia-Huey
CH
Jiang
I-Min
IM
Hsu
Tzu-Fang
TF