title: Voltage-controlled liquid-crystal terahertz phase shifter and quarter-wave plate.
abstract: Phase shift exceeding tau/2 at 1 THz is demonstrated by using electrically controlled birefringence in a homeotropically aligned nematic liquid crystal (E7) cell, 570 microm in thickness. The driving voltage required for a phase shift of 90 degrees is 125 V (rms). We demonstrate that the phase shifter works as an electrically switchable quarter-wave plate at 1 THz. The device can also be used as an electrically tuned phase compensator around the quarter-wave point near 1 THz.
authors.affiliation: Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan 30010.
authors.forename: Cho-Fan
authors.initials: CF
authors.lastname: Hsieh
authors.forename: Ru-Pin
authors.initials: RP
authors.lastname: Pan
authors.forename: Tsung-Ta
authors.initials: TT
authors.lastname: Tang
authors.forename: Hung-Lung
authors.initials: HL
authors.lastname: Chen
authors.forename: Ci-Ling
authors.initials: CL
authors.lastname: Pan