Abstract-Monolayer graphene based organic optical terahertz modulator

Guocui Wang, Bo Zhang, Hongyu Ji,   Xin Liu, Ting He, Longfeng Lv, Yanbing Hou,  Jingling Shen,

http://aip.scitation.org/doi/full/10.1063/1.4973816

We investigate a high-efficiency broadband terahertz wave modulator with structures made from the conjugated polymer [2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylennevinylene], graphene, and Si, irradiated with an external excitation laser. We demonstrate a strategy that can alleviate the tradeoff between the requirements of modulation depth and modulation speed in polymer/silicon terahertz wave modulators. Using terahertz time-domain and continuous-wave systems, we measured both the terahertz transmission modulation properties and the time responses of the modulator structures. The conjugated polymer/graphene/silicon structure achieved a high modulation factor of 93% for transmission as well as improved the modulation speed of the devices based on polymer/silicon. The high modulation efficiency of the polymer/graphene/silicon structure was induced by the enhancement in carrier density and the extremely high carrier mobility of graphene, respectively.

Abstract-Conjugated polymer based active electric-controlled terahertz device

Liang Zhong1, Bo Zhang1,a), Ting He1, Longfeng Lv2, Yanbing Hou2 andJingling Shen1,a





http://scitation.aip.org/content/aip/journal/apl/108/10/10.1063/1.4943648
http://scitation.aip.org/content/aip/journal/apl/108/10/10.1063/1.4943648







A modulation of terahertz response in a highly efficient, electric-controlled conjugated polymer-silicon hybrid device with low photo-excitation was investigated. The polymer-silicon forms a hybrid structure,where the active depletion region modifies the semiconductor conductivity in real time by applying an external bias voltage. The THz transmission was efficiently modulated by effective controlling. In a THz-TDS system, the modulation depth reached nearly 100% when the applied voltage was 3.8 V at an external laser intensity of 0.3 W/cm2. The saturation voltage decreased with increasing photo-excited intensity. In a THz-CW system, a significant decline in THz transmission was also observed with increasing applied bias voltage. This reduction in THz transmission is induced by the enhancement of carrier densit

Abstract-Active terahertz device based on optically controlled organometal halide perovskite

Bo Zhang^1,a), Longfeng Lv², Ting He¹, Tianji Chen¹, Mengdi Zang¹, Liang Zhong¹, Xinke Wang¹, Jingling Shen^1,a) and Yanbing Hou²
http://scitation.aip.org/content/aip/journal/apl/107/9/10.1063/1.4930164
a) Authors to whom correspondence should be addressed. Electronic addresses: bzhang@cnu.edu.cnand sjl-phy@cnu.edu.cn.
Appl. Phys. Lett. 107, 093301 (2015); http://dx.doi.org/10.1063/1.4930164

An active all-optical high-efficiency broadband terahertz device based on an organometal halideperovskite (CH3NH3PbI3, MAPbI3)/inorganic (Si) structure is investigated. Spectrally broadband modulation of the THz transmission is obtained in the frequency range from 0.2 to 2.6 THz, and a modulation depth of nearly 100% can be achieved with a low-level photoexcitation power (∼0.4 W/cm²). Both THz transmission and reflection were suppressed in the MAPbI3/Sistructure by an external continuous-wave (CW) laser. Enhancement of the charge carrier density at the MAPbI3/Si interface is crucial for photo-induced absorption. The results show that the proposed high-efficiency broadband optically controlled terahertz device based on the MAPbI3/Si structure has been realized.