title: Graphene based all-optical spatial terahertz modulator.
abstract: We demonstrate an all-optical terahertz modulator based on single-layer graphene on germanium (GOG), which can be driven by a 1.55 μm CW laser with a low-level photodoping power. Both the static and dynamic THz transmission modulation experiments were carried out. A spectrally wide-band modulation of the THz transmission is obtained in a frequency range from 0.25 to 1 THz, and a modulation depth of 94% can be achieved if proper pump power is applied. The modulation speed of the modulator was measured to be ~ 200 KHz using a 340 GHz carrier. A theoretical model is proposed for the modulator and the calculation results indicate that the enhanced THz modulation is mainly due to the third order nonlinear effect in the optical conductivity of the graphene monolayer.
authors.affiliation: State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Qi-Ye
authors.initials: QY
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Mao
authors.affiliation: National Key Laboratory of Science and Technology of Communication. University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Institute of Modern Optics, Nankai University, Key Laboratory of Optical Information Science and Technology, Ministry of Education, Tianjin, 300071, P.R. China.
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Qing-Hui
authors.initials: QH
authors.lastname: Yang
authors.affiliation: School of Physics, University of Wollongong, NSW 2522, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Sanderson
authors.affiliation: State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
authors.forename: Huai-Wu
authors.initials: HW
authors.lastname: Zhang