title: A Low Voltage Liquid Crystal Phase Grating with Switchable Diffraction Angles.
abstract: We demonstrate a simple yet high performance phase grating with switchable diffraction angles using a fringe field switching (FFS) liquid crystal (LC) cell. The LC rubbing angle is parallel to the FFS electrodes (i.e. α = 0°), leading to symmetric LC director distribution in a voltage-on state. Such a grating exhibits three unique features: 1) Two grating periods can be formed by controlling the applied voltage, resulting in switchable diffraction angles. In our design, the 1stdiffraction order occurs at 4.3°, while the 2ndorder appears at 8.6°. 2) The required voltage to achieve peak diffraction efficiency (η~32%) for the 1storder is only 4.4 V at λ = 633 nm as compared to 70 V for a conventional FFS-based phase grating in which α ≈ 7°, while the 2ndorder (η~27%) is 15 V. 3). The measured rise and decay time for the 1storder is 7.62 ms and 6.75 ms, and for the 2ndorder is 0.75 ms and 3.87 ms, respectively. To understand the physical mechanisms, we also perform device simulations. Good agreement between experiment and simulation is obtained.
authors.affiliation: College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Haiwei
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Guanjun
authors.initials: G
authors.lastname: Tan
authors.affiliation: College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Yuge
authors.initials: Y
authors.lastname: Huang
authors.affiliation: College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.|School of Electronic Science and Engineering, Southeast University, Nanjing 210018, China.
authors.forename: Yishi
authors.initials: Y
authors.lastname: Weng
authors.affiliation: Department of Electronics Engineering, Pusan National University, Busan 46241, Korea.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Choi
authors.affiliation: Department of Electronics Engineering, Pusan National University, Busan 46241, Korea.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Yoon
authors.affiliation: College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: Shin-Tson
authors.initials: ST
authors.lastname: Wu