Abstract-Temperature-controlled terahertz polarization conversion bandwidth

 

Jing Zhao, Chunmei Ouyang, Xieyu Chen, Yanfeng Li, Caihong Zhang, Longcheng Feng, Biaobing Jin, Jiajun Ma, Yi Liu, Shoujun Zhang, Quan Xu, Jiaguang Han,  Weili Zhang, 

Schematic diagram of the metasurface structure and experimental system. (a) Unit cell, composed of sapphire substrate, VO2 and gold SRRs layers, polyimide dielectric layer and a gold grating, with geometrical parameters h = 2000 µm, P = 80 µm, d = 200 nm, t = 35 µm, d1 = 10 µm, and d2 = 22 µm. (b) Vertical view of the unit cell. (c) Gold SRR with geometrical parameters O = 10°, O1 = 10°, C1 = 30°, and C2 = 45°. (d)-(f) Optical microscope images of the fabricated VO2 and gold SRRs, gold grating and their combined structure, respectively. (g) Sample characterization by THz-TDS.

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-29-14-21738&id=452731

Active control of metasurfaces has attracted widespread attention because of the adjustable electromagnetic properties obtained. Here we designed and experimentally studied a dynamically controllable polarization converter in the terahertz band. By designing the structural parameters and utilizing the insulator-to-metal phase transition of vanadium dioxide and principle of current resonance, dynamic tunability of the polarization conversion function from dual-broadband (0.45∼0.77 THz and 0.97∼1.2 THz) to ultra-broadband (0.38∼1.20 THz) can be realized with a high polarization conversion ratio. The scheme proposed here can find potential applications in integrated terahertz systems, sensing, imaging and communications areas.

© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Tunable terahertz transmission properties of aligned Ni-nanowire arrays

Wenfeng Xiang, Yi Liu, Minghao Hu, and Haizhong Guo

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-24-30606

Aligned Ni nanowire (NW) arrays were investigated for terahertz (THz) wave modulation. By adjusting the NW density and order of the NW arrays, the resonant frequency and intensity of the THz waves can be effectively tuned. The tuning range of the resonant frequency is about 0.29 THz, and a transmittance of less than 40% in the frequency region from 0.5 to 2 THz is achieved by changing the NW density. Although the order of the NW arrays has no influence on the resonant frequency, the transmittance can be tuned about 21%. The ability to tune the intensity and resonant frequency effectively and the ease of fabrication of the Ni-NW arrays make them the potential candidates for THz tunable filters, intensity modulators, and spatial light modulators.

© 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Effect of an external electric field on the coherent terahertz emission from multiple filaments in air

• Sergey I. Mitryukovskiy, 
• Yi Liu, 
• Bernard Prade, 
• Aurélien Houard, 
• André Mysyrowicz

http://link.springer.com/article/10.1007/s00340-014-5830-1

We describe the terahertz emission from multiple filaments in air in the presence of an external electric field. A strong enhancement of the radiated terahertz energy is obtained by the combined effect of terahertz field interference and presence of a static electric field. 

Abstract-Coherent synthesis of terahertz radiation from femtosecond laser filaments in air

Sergey I. Mitryukovskiy, Yi Liu, Bernard Prade, Aurélien Houard, and André Mysyrowicz

Laboratoire d'Optique Appliquée, ENSTA ParisTech/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau, F-91762, France 

http://apl.aip.org/resource/1/applab/v102/i22/p221107_s1?isAuthorized=no

We report on the coherent synthesis of pulsed terahertz radiation from femtosecond laser filaments organized in an array. The terahertz intensity is proportional to the square of the number of the filaments, which provides a simple method for scaling up of the terahertz energy with a powerful femtosecond laser. Moreover, directional off-axis terahertz radiation can be achieved. This paves the way for applications of this terahertz source for remote sensing.

© 2013 AIP Publishing LLC