Research Article Polarization Sensitive Reflection and Dielectric Spectra in GaSe Thin Films Hazem K. Khanfar 1 and Atef A. Qasrawi 2,3 1 Department of Telecommunication Engineering, Arab-American University, Jenin, State of Palestine 2 Department of Physics, Arab-American University, Jenin, West Bank, State of Palestine 3 Group of Physics, Faculty of Engineering, Atilim University, 06836 Ankara, Turkey Correspondence should be addressed to Atef A. Qasrawi; atef.qasrawi@atilim.edu.tr Received 10 March 2016; Revised 16 June 2016; Accepted 5 July 2016 Academic Editor: Armin Gerhard Aberle Copyright © 2016 H. K. Khanfar and A. A. Qasrawi. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te light polarization efects on the optical refective and dielectric spectra of GaSe thin flms are studied in the incident light wavelength range of 200–1100 nm. In this range of measurement, the angle of incidence (  ) of light was varied between 30 ∘ and 80 ∘ . In addition, at   of 30 ∘ the light polarizing angle () was altered in the range of 0–90 ∘ . Regardless of the value of , for all   ≻ 65 ∘ , the total refectance sharply decreased with increasing   . In addition, when   is fxed at 30 ∘ and  was varied, the amplitudes ratio of the polarized waves exhibits a resonance-antiresonance phenomenon at a wavelength that coincides with the flm’s thickness (800 nm). Tis behavior was assigned to the coupled interference between incident and refected waves and to the strong absorption efects. Two main resonance peaks are observed as response to -polarized and normal incident beam: one is at ∼540 (556 nm) and the other at ∼420 THz (714 nm). Te dielectric constant of the GaSe flms exhibits anisotropic characteristics that nominate it for use as multipurpose optoelectronic devices. 1. Introduction Optical communications technologies, which include visible light communication (VLC), free space optical communica- tion (FSO), Li-Fi, and infrared data transformers, are one important part of our daily life needs. Data transformations using the VLC technology, which get use of light in the frequency range of 400–800 THz, are very new and attract the focus of much research and development centers. In a trail to use VLC system for data transformation, in the year 2010, a 500 Mbit/s data transformation rate over few meters’ distance was successfully actualized using white LED (light emitting diode) as encoding light source [1, 2]. In the following year a live high-defnition video was transmitted from a standard LED lamp by TED Global. However, long distance (∼1.5 km) data transformation is still actualized at low rates. Te VLC technology translates the optical data to electri- cal signal via photosensitive substrates. In this operation, the time it takes to switch on and of electric current determines the rate at which signals can be processed [3]. In addition, the control of electric current on a subpicosecond timescale in semiconductors is now possible through the optical injec- tion of currents by the help of interfering photoexcitation pathways [3, 4] or photoconductive switching of terahertz transients. Te reversibility of the AC conductivity in silica is reported to be enhanced by 18 times in one femtosecond [5] by the incident electric feld (light wave) polarization. In the scope of these requirements and developments there is a need to fnd new types of optical substrates that allow electric feld interference in the visible region to ft with the VLC technology needs. One of these substrates is the well-known photovoltaic copper indium gallium selenide photocell [6]. A TD06006M-01278 C05-33 copper indium gallium selenide photocell of 80 × 45 mm dimensions was used to analyze Li- Fi performances under diferent lighting conditions. Tis cell has revealed a band width up to 4.2 MHz at 80 lx DC. On the other hand, when the gallium selenide optoelectronic device is excited with a 405 nm laser at a power of 0.5 mW/mm 2 it refected a dark to light current ratio of the order 10 3 [7]. Te photoresponsivity and quantum efciency of this device Hindawi Publishing Corporation Advances in OptoElectronics Volume 2016, Article ID 7182303, 7 pages http://dx.doi.org/10.1155/2016/7182303