Abstract-Terahertz absorber based on Fano-like resonance of inverted quadrangular frustum pyramid metal grooves and sensor application

Yingying Yu,  Bo Sun,

http://iopscience.iop.org/article/10.1088/2040-8986/aac842/pdf

We investigate the multi-resonance coupling of inverted quadrangular frustum pyramid groove metal arrays at terahertz frequencies. The surface plasmon resonance (SPR) and groove resonance are induced, resulting in resonance coupling. The dipole of the groove resonance drives the quadrupole of the SPR and creates a sharp Fano-like resonance. The effects of geometry parameters including the width (at the bottom) and height are analyzed in detail. The results show that with the decrease in the sidewall slope of the groove, the confinement of the groove region on the electromagnetic field decreases, thereby increasing the resonance coupling. The Fano-like resonance is enhanced. The sensitivity and quality factor are discussed. The results show that the Fano-like resonance has high sensitivity and quality factor. With the increase in the sidewall slope of the groove, the sensitivity increases, and the quality factor decreases. The results show that the Fano-like resonance of inverted quadrangular frustum pyramid groove metal arrays has a significant potential for biological monitoring and sensing.

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Abstract-Large-area flexible photodetector based on atomically thin MoS2/graphene film

Bo Sun, Tielin Shi, Zhiyong Liu, Youni Wu, Jianxin Zhou, Guanglan Liao

https://www.sciencedirect.com/science/article/pii/S0264127518303964


In this paper, we demonstrate a large-area flexible photodetector based on vertically stacked atomically thin MoS₂/graphene film. The MoS₂ film is grown by CVD method. We have realized the growth of several square millimeter continuous monolayer MoS₂ film via precisely control the atmosphere and temperature in the tube furnace. In experiment, the MoS₂ and graphene film was transferred on PET substrate successively. Polymer electrolyte composed of PEO and LiClO₄ was introduced to fabricate the side-gated flexible photodetector. The devices exhibit high performance at low operation voltage. External responsivity is about 3.5 A/W at V_gs = −1 V, V_ds = 1 V with incident power of 60 μW (520 nm). Noteworthy is that the transmittance of the heterostructure at 520 nm is only about 10.5%, the internal responsivity even reaches to about 33.3 A/W, which is higher than most of the flexible photodetectors based on nanomaterials. Besides, the devices display high stability during transient on/off test. We believe the MoS₂/graphene photodetector would be a promising candidate in flexible electronic system. Besides, such hybrid film design is also portable and meaningful for future photodetector investigation.

Abstract-Investigation of a terahertz-wave parametric oscillator using LiTaO3 with the pump-wavelength tuning method

Bo Sun1, Xianpeng Bai1, Jinsong Liu2 and Jianquan Yao3

sunbo_xt@hotmail.com

http://iopscience.iop.org/1555-6611/24/3/035402/pdf/1555-6611_24_3_035402.pdf

1 Institute of Photonics and Photonic Technology, Northwest University, Xi'an 710069, People's Republic of China
2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
3 College of Precision and Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, People's Republic of China
 

Bo Sun et al 2014 Laser Phys. 24 035402. doi:10.1088/1054-660X/24/3/035402
Received 2 November 2013, accepted for publication 24 December 2013. Published 3 February 2014.
© 2014 Astro Ltd

We investigate theoretically the performance of a terahertz parametric oscillator (TPO) using LiTaO3 (LT) with the pump-wavelength tuning method. The frequency tuning accuracy of the LT-TPO is potentially superior to that of a TPO using LiNbO3 (LN) under the same conditions. The variation of the radiation angle of THz waves coupled from the Si prism of the LT-TPO is up to about 20° lower than that for the LN-TPO for a pump-wavelength tuning range of 0.4–1.6 μm. Although the THz-wave parametric gain characteristics of LiTaO3 are somewhat unsatisfactory compared with those of LiNbO3, the LT-TPO with pump-wavelength tuning can still show potential for high-performance operation, with the excellent optical properties of the LiTaO3.