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Published in Vladimir Mitin, Taiichi Otsuji, Victor Ryzhii, Graphene-Based Terahertz Electronics and Plasmonics, 2020
T. Itatsu, E. Sano, Y. Yabe, V. Ryzhii, T. Otsuji
The development of compact, low-cost sources and detectors operating at room temperature is needed to fully use terahertz (THz) electromagnetic waves in a variety of applications. Photo-excited graphene is expected to exhibit population inversion and enable the fabrication of a novel THz laser. We previously proposed a THz amplifier as a basic element in a THz laser by combining the population inversion in photo-excited graphene with the electric field enhancement due to the spoof surface plasmon polaritons induced on the surface of a metal mesh structure. For this work, we fabricated prototype THz amplifiers composed of chemical-vapor-deposition-grown graphene and a metal mesh structure and observed extremely amplified THz emission by using an electro-optic sampling method.
Gerald J. Wilmink
Published in James C. Lin, Electromagnetic Fields in Biological Systems, 2016
Gerald J. Wilmink, Jessica E. Grundt
New design methods are currently being explored to develop more efficient THz QCLs, which operate at room temperature, emit radiation at lower frequencies (0.1–1.5 THz), and that better collimate the ever diverging THz beam. For example, in a recent study, Yu et al. demonstrated that spoof surface plasmon structures can be used to dramatically reduce beam divergence and increase their power collection efficiency by a factor of 6 (Yu et al. 2010). If scientists continue to address these challenges, the compact nature and high power of THz-QCLs make them a very promising source for future bioeffects studies. For additional details on THz QCLs, we refer the reader to an excellent review by Williams (2007).
Intersubband Optoelectronics Using III-Nitride Semiconductors
Published in Wengang (Wayne) Bi, Hao-chung (Henry) Kuo, Pei-Cheng Ku, Bo Shen, Handbook of GaN Semiconductor Materials and Devices, 2017
Caroline B. Lim, Akhil Ajay, Jonas Lähnemann, David A. Browne, Eva Monroy
Sun et al. (2013) have modelled a QCL structure based on a 3-well design that depopulates via the LO phonon and emits at 6.77 THz (λ = 44.3 µm), and have proposed the use of a spoof surface plasmon waveguide instead of a normal surface plasmon waveguide, which should result in an order of magnitude lower losses in the guiding structure.
Beam scanning leaky wave antenna based on liquid crystals with gesture-controlled system
Published in Liquid Crystals, 2023
Chang Ding, Yudeng Wang, Yajuan Han, Xinmin Fu, Ruichao Zhu, Huilin Mu, Fanyi Meng, Jiafu Wang
In this paper, as shown in Figure 1, one novel framework which realises contactless gesture-controlled beam scanning LWA using one gesture recognition module is proposed. This framework consists of three parts, i.e. sensor, controller, and actuator. The sensor is a gesture recognition module utilised to extract gesture information. The obtained information is transmitted to the controller which consists of microprogrammed control unit (MCU) and output terminal. Different-biased voltage signals are produced and imposed on the actuator, which is a novel LC-based LWA designed by a spoof surface plasmon polaritons (SSPP) transmission line with periodic vivaldi patches. The output voltage from the controller denotes the state of LC molecules, so as to control the radiation characteristic of the beam scanning antenna. The prototype of the proposed framework is fabricated and measured to verify the effectiveness. Different from the traditional beam scanning antennas, this proposed antenna can be controlled through the real-time response of different gestures. Our design maps different gestures into antenna radiation regulation, which effectively increases the convenience. This work paves a new way to intelligent antennas and may find applications in IoT communications, 5 G/6 G communications and smart sensors.
Tunable balanced liquid crystal phase shifter based on spoof surface plasmon polaritons with common-mode suppression
Published in Liquid Crystals, 2020
Chang Ding, Fan-Yi Meng, Tao Jin, Jian-Feng lv, Hui-Lin Mu, Qun Wu
In view of the above-mentioned issues, a novel design approach for the LC-based tunable balanced phase shifter with the CM suppression is proposed in this paper. Firstly, the phase shift mechanism of the balanced phase shifter based on the Spoof Surface Plasmon Polariton (SSPP) is investigated. The specific roles of the LC-based SSPP differential line (SSPP-DL) in improving phase shifts and Figure of Merit (FoM, it equals to the ratio of the maximum tunable phase shift and the maximum insertion loss) are studied. And then, in order to suppress the CM noise, the defected ground structure based on slotted dumbbell-shaped resonators is employed. The corresponding theoretical analysis is conducted to declare the operating principle. A prototype sample is designed, fabricated, and tested to validate the proposed design method. Experimental results are in good agreement with theoretical predictions and numerical simulations.
A compact, high gain, spoof surface plasmon polariton sawtooth end-fire antenna
Published in Journal of Modern Optics, 2020
Binggang Xiao, Xiao Tu, Alexander Fyffe, Xiumin Wang, Zhimin Shi
Surface plasmon polaritons (SPPs) are surface waves propagating along the interface between a metal and a dielectric [1]. These surface waves exhibit high spatial confinement and decay exponentially in the transverse direction due to the negative permittivity of the metal. SPPs have the advantage of confining the electromagnetic wave to the sub-wavelength region, proving useful for device miniaturization [2]. It has been demonstrated that spoof SPPs can be excited in the microwave and terahertz frequency band by etching periodic grooves on the surface of a metal [3]. The cut-off frequency can be controlled by adjusting the geometrical parameters of the grooves, which consequently determines the transmission characteristics of spoof SPPs [3]. Spoof SPPs have similar performance to natural SPPs, including the properties of dispersion relationships, strong field confinement at the subwavelength range, and high signal integrity [4]. The discovery of spoof surface plasmon polaritons has generated tremendous interest in the scientific and engineering communities due to their excellent performance in device integration and miniaturization in the terahertz and microwave frequency regimes [5,6]. To date, circuit devices loaded on to spoof SPP waveguides have been applied to splitters [7,8], absorbers [9], filters [10,11], power dividers [12,13] and antennas [14–17].