NIR Light Driven Terahertz Wave Modulator with a Large Modulation Depth Based on a Silicon‐PEDOT:PSS‐Perovskite Hybrid System

2020 ◽  
Vol 5 (4) ◽  
pp. 1901090
Author(s):  
Weien Lai ◽  
Chengda Ge ◽  
Hao Yuan ◽  
Qingfeng Dong ◽  
Deren Yang ◽  
...  
2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shuqing Chen ◽  
Zhiqiang Xie ◽  
Junmin Liu ◽  
Yanliang He ◽  
Yao Cai ◽  
...  

By using optical heterodyne technique, we demonstrated the stable emission of sub-terahertz wave with the frequency ranging from 88 GHz to 101 GHz, which can operate as microwave source for nonlinear response measurement system. Mutual frequency beating of two well-separated sideband signals at a 0.1 THz photo-detector (PD) allows for the generation of sub-terahertz signal. Based on this approach, we have achieved the radiation of 0.1 THz wave with power up to 4 mW. By transmittance measurement, two-dimensional nanomaterial topological insulator (TI: Bi2Te3) shows saturable absorption behaviors with normalized modulation depth of 47% at 0.1 THz. Our results show that optical heterodyne technique could be developed as an effective microwave source generation for nonlinear measurement at sub-terahertz, even terahertz band.


Author(s):  
L. C. Maxey ◽  
J. E. Parks ◽  
D. L. Beshears ◽  
D. D. Earl ◽  
M. V. Lapsa ◽  
...  

Increased use of solar energy will reduce requirements for non-renewable energy sources such as fossil fuels and reduce associated greenhouse gas emissions. The benefits of replacing fossil-based energy with solar energy are often dependent on the application and operational or duty cycle for power demand. One particularly efficient use of solar energy is hybrid lighting. In hybrid lighting, solar light is concentrated into optical fibers and then coupled with supplemental electrical lighting to maintain a constant level of illumination. The system is able to offer reliable lighting with less energy consumption from the electrical grid (which is often driven by non-renewable sources). This technique offers energy efficiency benefits since the solar light is used directly and suffers no conversion losses. Furthermore, the solar spectrum provides an illumination that lighting engineers value for it’s quality; office inhabitants appreciate for its comfort; and retailers believe leads to increased sales. When available solar light is low, the hybrid system allows traditional light sources to reliably meet lighting demands. The success of the solar hybrid lighting system is dependent on the collection and transmission efficiency of the system. In this study, the spectral transmission of a hybrid lighting system is characterized. The system is composed of a 200-sun concentration reflective solar collector and a plastic fiber optic distribution network. The ultraviolet (UV), visible, and near-infrared (NIR) spectral transmission was characterized over a spectral range of 200 nm to 2400 nm. The UV and NIR performance of the system is critical since optical fiber damage can be caused by both UV and NIR light; thus, optimal system design maximizes the collection and transmission of visible light while minimizing the transmission of the UV and NIR light. Spectral transmission data for all components in the hybrid system are presented, and performance properties relative to solar applications are discussed.


2019 ◽  
Vol 9 (3) ◽  
pp. 507 ◽  
Author(s):  
Liangping Xia ◽  
Xin Zhang ◽  
Man Zhang ◽  
Suihu Dang ◽  
Shijian Huang ◽  
...  

A terahertz modulation structure based on hybrid metamaterial and graphene is proposed and demonstrated in this work. The metamaterial with a square slit ring array excites terahertz resonance in the slits and enhances the interaction between the terahertz wave and graphene. The graphene layer acting as the active material is tuned by the applied electrical field. With the separation by a dielectric layer between the graphene and the metallic structure, the resonant frequency and transmitted energy are both modulated by the graphene. Experimental result indicates that the modulation depth of the terahertz transmitted amplitude is 65.1% when the applied modulation voltage is tuned 5 V.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Miaoqing Wei ◽  
Dainan Zhang ◽  
Lei Zhang ◽  
Lichuan Jin ◽  
Huaiwu Zhang

Abstract In this paper, we have reported a multifunctional device from graphene/TiO2/p-Si heterojunction, followed by its systematical analysis of optical response in a device under ultraviolet–visible-infrared band and transmission changes of terahertz waves in the 0.3–1.0 THz band under different bias voltages. It is found that photodetector in the “back-to-back” p-n-p energy band structure has a seriously unbalanced distribution of photogenerated carriers in the vertical direction when light is irradiated from the graphene side. So this ensures a higher optical gain of the device in the form of up to 3.6 A/W responsivities and 4 × 1013 Jones detectability under 750 nm laser irradiation. Besides, the addition of TiO2 layer in this terahertz modulator continuously widens the carrier depletion region under negative bias, thereby realizing modulation of the terahertz wave, making the modulation depth up to 23% under − 15 V bias. However, almost no change is observed in the transmission of terahertz wave when a positive bias is applied. A similar of an electronic semiconductor diode is observed that only allows the passage of terahertz wave for negative bias and blocks the positive ones. Graphic Abstract


2021 ◽  
Author(s):  
Lichuan Jin ◽  
Miaoqing Wei ◽  
Dainan Zhang ◽  
Lei Zhang ◽  
Huaiwu Zhang

Abstract In this paper, we have prepared a multifunctional device based on graphene/TiO2/p-Si heterojunction and systematically studied the optical response of the device in the ultraviolet-visible-infrared band and the transmission changes of terahertz waves in the 0.3-1.0 THz band under different bias voltages. As a photodetector, the “back-to-back” p-n-p energy band structure makes the device have a serious unbalanced distribution of photogenerated carriers in the vertical direction when light is incident from the graphene side, which ensures a higher optical gain of the device, so as to achieve a responsivity up to 3.6 A/W and a detectability of 4×1013 Jones under 750 nm laser irradiation. As a terahertz modulator, the addition of the TiO2 layer allows the device to continuously widen the carrier depletion region under negative bias, thereby realizing modulation of the terahertz wave, making the modulation depth up to 23% under − 15 V bias. However, there is almost no change in the transmission of the terahertz wave when positive bias is applied. An analogue of an electronic semiconductor diode effect is realized that allows passage of the terahertz wave only for negative bias and blocks the terahertz wave while positively biased.


Author(s):  
H Rempp ◽  
S Clasen ◽  
M Voigtländer ◽  
S Kempf ◽  
A Weihusen ◽  
...  
Keyword(s):  

2014 ◽  
Vol 13 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Hak-Song Jeon ◽  
◽  
Jong-Min Kim ◽  
Kwang-Han Bae ◽  
Tae-Oh Kim

2016 ◽  
Vol 14 (4) ◽  
pp. 388-414
Author(s):  
Alexandra P. Mikroulea

AbstractOpt-in or opt-out? That is the basic question to be answered. The decision to promote actions of “opt-in” type as opposed to those of the “opt-out” type, for the sake of private autonomy, does not ensure the effective application of european competition law. On the contrary, it may decrease the application’s intensity and effectiveness. Recent reforms among European state members such as in the United Kingdom, Belgium, the Netherlands, Denmark and Norway are powerful indications that the opt-out principle may result in the effective implementation of competition law. There is no doubt that a mixed system (hybrid system), providing the court with the power to decide in favour of either the opt-in or the opt-out system, will result in better implementation of competition law. At the present time there are two pending cases in England (Dorothy Gibson and Mastercard) for which the decision on opt-out or opt-in are highly anticipated. Should the court decide, in one or both of the cases, on an opt-out approach, this will bring a momentous reevaluation of the entire collective redress concept.


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