- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Terahertz Spectroscopy of Different Phenotypes of Arabidopsis Thaliana
摘要： The recent surge in ‘Precision agriculture’ is fueled by the acute need of food security felt worldwide to feed the global burgeoning population. To this effect, various optical techniques have recently been employed to characterize the biochemical processes in various parts of the plants [1]. Terahertz (THz) region (0.3 – 10 THz) has gathered momentum in this field as it is biologically safe, can penetrate food packaging and most importantly, has fingerprinting ability of various organic and inorganic molecules due to active rotational and vibrational modes [2]. Moreover, unlike other optical spectroscopic techniques, THz time domain spectroscopic (THz-TDS) technique records the information in form of THz electric field; which once converted to frequency domain provides both amplitude and phase information [3]. Additionally, THz waves are highly absorbed by water which in turn can be utilized for quantitative water status monitoring in plants [4]. In this work, we have used THz-TDS with a bandwidth over 5 THz for the detection of biochemicals present in two different T-DNA insertion mutants in two independent genes of Arabidopsis thaliana (Col-0 Columbia ecotype). The plants were grown from mutant seeds in controlled environment. For easier optical access to all parts of the plants, the seedlings were grown parallel to the surface in a petri dish of plant growth medium. Liu et al. has already reported successful discrimination of transgenic Soybean seeds using THz spectroscopy [5]. We have recorded spectroscopic data of several parts of all the mutant plants which were 5, 7, 12 and 13 days old kept under identical conditions. The time domain spectrum obtained from the experiment was converted to frequency domain. Figure 1 shows the frequency domain spectrum of one such set of spectroscopic data collected from the stem part of the two different mutants compared to wild type control Col-0 plants. As it is evident from the spectrum, there are many absorption peaks corresponding to water and other biochemical molecules. For example, the peaks at 1.7 THz and 2.6 THz corresponds to sucrose present in the plants and in the nutri-solution which has been taken as the reference [2]. Our ongoing study involves careful analysis of the variations of the molecular absorption peaks for different mutants which would not only enable a label-free genetic identification, but also would help in our understanding of the underlying shift in biochemical processes contributed by the specific gene.
关键词： Terahertz spectroscopy,Arabidopsis thaliana,THz-TDS,Precision agriculture,biochemical processes
更新于2025-09-16 10:30:52
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Wireless Terahertz Communications
摘要： Over the past years, interest in wireless THz communications with so-called T-waves has tremendously increased [1]–[4], because the large carrier frequencies in the range 0.2 THz to 0.9 THz support wide signal bandwidths and consequently large data rates. Transmission over hundreds of meters and line rates exceeding 100 Gbit/s were demonstrated [5]–[10]. Typical atmospheric losses are 0.2 dB/100 m at 0.2 THz, 0.5 dB/100 m at 0.3 THz, 1.5 dB/100 m at 0.4 THz, and 5 dB/100 m at 0.9 THz. For transmission over a 100 m-distance, however, the unity-gain free-space propagation loss dominates. To combat this propagation loss, multiple directional antennas with a high gain per sector can be employed at the base station to boost the reach and the data throughput on transmission and reception.
关键词： T-waves,wireless THz communications,coherent reception,optoelectronic signal processing,photomixing
更新于2025-09-16 10:30:52
-
[IEEE 2019 49th European Microwave Conference (EuMC) - Paris, France (2019.10.1-2019.10.3)] 2019 49th European Microwave Conference (EuMC) - Conductor-backed coplanar waveguide on BCB with thin metal layers and via holes
摘要： A process for microelectronic technology is developed for integration of passive devices with existing active device technology for submillimeter wave and THz frequency range applications. Performances of a conductor-backed coplanar waveguide on BCB polymer and interconnecting via between ground planes are presented up to 67 GHz with a 50 Ω characteristic impedance and a BCB relative permittivity of 2.676.
关键词： THz coplanar waveguides,polymer dielectric,submillimeter wave waveguides,transmission lines
更新于2025-09-16 10:30:52
-
Influence of exciton energy on intersubband transition of chirped superlattice GaAs/AlGaAs quantum cascade laser
摘要： The influence of exciton energy on intersubband transition was simulated for a chirped supperlattice quantum cascade laser of GaAs/AlxGa1-xAs. Exciton energy was modelled as a function of QW width for alloys of various percentages of constituent elements. The results showed that the exciton energy decreased proportionally with increasing QW width. Models were also generated to study exciton energy as a function of the percent alloy contents of AlxGa1-xAs barriers for QWs of various widths. Exciton energy showed characteristics of higher discrete energy when QW width was narrower. Transition energy was also simulated from 1e and 2e to the 1s exciton state as functions of applied electric field at various QW widths. Our simulation results showed that the transition energy from 2e to the 1s exciton state increased proportionally to the increasing strength of the electric field. This transition energy was indicative of THz range radiation.
关键词： percent alloy contents,chirped superlattice quantum cascade laser,aluminum arsenide monolayer,THz radiation,transition energy
更新于2025-09-16 10:30:52
-
Electronic–Electromagnetic Multiphysics Modeling for Terahertz Plasmonics: A Review
摘要： In this article, we review numerical and analytical methods of electronic–electromagnetic multiphysics modeling for terahertz plasmonic applications. Approaches within semiclassical regime of electronic transport are considered, as these are appropriate for examining plasma-wave phenomenology in 2-D electron gas systems, commonly found in high-electron-mobility transistors (HEMTs) and graphene sheets. In modeling of such electronic–plasmonic devices, coupling of incident electromagnetic wave to the device or emission from the device needs to be modeled. Therefore, electronic–electromagnetic coupled multiphysics multiscale models are required. In such modeling problems, the domain consists of large regions where electrodynamic equations are to be solved. Therefore, overall time efficiency relies on the speed of solution of electrodynamic equations. Nevertheless, the electrodynamic solution’s speed is limited by the smallest grid sizes, which are a function of electronic transport equations. To address these issues, unconditionally stable finite-difference time-domain (FDTD) and iterative alternating directional implicit (ADI)-FDTD methods, coupled with hydrodynamic equations, are reviewed. Advantages and compromises between FDTD, ADI-FDTD, and iterative ADI-FDTD-based global modeling are discussed and conclusions are summarized.
关键词： electronic,numerical modeling,electron transport,terahertz (THz),FDTD,multiphysics,plasmonic,Alternating directional implicit finite-difference time-domain (ADI-FDTD),multiscale modeling,hydrodynamic (HD),plasma wave,electromagnetic
更新于2025-09-16 10:30:52
-
Mathematical Modelling of Electrically Controlled Filters of Microwave, subTHz and THza??bands on the Base of Grapheneand-Dielectric Multilayer Structure
摘要： Report is devoted to investigations of graphene meta–surfaces for the transmission of radiation induced by plasmons in subTHz and THz ranges, cell of which consists of structures based on graphene ring and graphene nano–tape. It create regimes of radiation transmission – transparency windows induced by electric dipole resonances. Resonant frequency of transparency window can be dynamically tuned in wide band of subTHz and THz bands by changing the chemical potential (Fermi energy) of graphene by applying external electric field (gating) instead of re–fabricating of structures. Questions of possibilities of electronic controlled filters creating of subTHz and THz bands grounded on different configurations of graphene meta–surfaces are discussed; their characteristics and frequency dependencies are investigated. Mathematical modelling and electrodynamic calculation of the filters characteristics of subTHz and THz bands grounded on multilayer structures of “graphene–dielectric” type are carried out. From results of mathematical modelling it follows that periodic layered microstructures “graphene–dielectric” type can be used for creation of subTHz and THz bands broadband filters of planar construction, controlling by electric field and fast tuning at small changes in Fermi energy level of graphene.
关键词： multilayer structures,filters,subTHz,plasmonic,chemical potential,electric field,graphene,meta-surfaces,electric dipole resonances,THz,Fermi energy
更新于2025-09-16 10:30:52
-
The detection of sub-terahertz radiation using graphene-layer and graphene-nanoribbon FETs with asymmetric contacts
摘要： We report on the detection of sub-terahertz radiation using single layer graphene and graphene-nanoribbon FETs with asymmetric contacts (one is the Schottky contact and one – the Ohmic contact). We found that cutting graphene into ribbons a hundred nanometers wide leads to a decrease of the response to sub-THz radiation. We show that suppression of the response in the graphene nanoribbons devices can be explained by unusual properties of the Schottky barrier on graphene-vanadium interface.
关键词： detector,THz region,graphene,terahertz radiation,graphene nanoribbons,optoelectronics
更新于2025-09-16 10:30:52
-
[IEEE 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Padang, Indonesia (2019.7.22-2019.7.24)] 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Room-Temperature Terahertz Antenna-Coupled Microbolometers with Titanium Thermistor and Heater
摘要： High-detectivity room-temperature terahertz (THz) detectors are expected to be utilized in spectroscopy and imaging for such applications as nondestructive inspection for safety, construction, noninvasive examination for medicine and pharmacy. We have studied THz antenna-coupled bolometers with titanium (Ti) thermistor and heater fabricated on a high-resistivity silicon (Si) substrate with MEMS structures in order to develop uncooled high-performance sensors. In this paper, we report the study on design, electromagnetic (EM) and thermal simulation, fabrication, experiment of THz-wave measurement, and evaluation of performance for single-detector devices, by which large THz array detectors are easily developed. We have achieved good performance as low noise-equivalent power (NEP) of the orders of 10-11 W/Hz1/2 and response frequency of 5.5 kHz by studying a Ti thermistor with thin meander line for the THz antenna-coupled bolometer.
关键词： nondestructive,terahertz (THz),meander line,sensing,thermistor,noise equivalent power (NEP),temperature coefficient of resistance (TCR),responsivity,bolometer,room temperature,uncooled,detector,array
更新于2025-09-16 10:30:52
-
[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Drift-induced Nonreciprocal Graphene Plasmonics
摘要： We present a detailed investigation of the responsivity and the noise in room temperature THz direct detectors made of YBa Cu O (YBCO) thin-film nano-bolometers. The YBCO nano-bolometers are integrated with planar spiral antennas covering a frequency range from 100 GHz to 2 THz. The detectors were characterized at 1.6 THz, 0.7 THz, 400 GHz and 100 GHz. The maximum electrical responsivity of 70 V/W and a minimum noise equivalent power (NEP) of 50 pW/Hz were measured, whereas the highest optical responsivity was 45 V/W. The noise in nano-bolometers is independent on the device volume and for a given modulation frequency and a dc voltage.
关键词： THz detectors,YBa Cu O (YBCO) film,responsivity,room temperature operation,Bolometer
更新于2025-09-16 10:30:52
-
Key Roles of Plasmonics in Wireless THz Nanocommunicationsa??A Survey
摘要： Wireless data traffic has experienced an unprecedented boost in past years, and according to data traffic forecasts, within a decade, it is expected to compete sufficiently with wired broadband infrastructure. Therefore, the use of even higher carrier frequency bands in the THz range, via adoption of new technologies to equip future THz band wireless communication systems at the nanoscale is required, in order to accommodate a variety of applications, that would satisfy the ever increasing user demands of higher data rates. Certain wireless applications such as 5G and beyond communications, network on chip system architectures, and nanosensor networks, will no longer satisfy speed and latency demands with existing technologies and system architectures. Apart from conventional CMOS technology, and the already tested, still promising though, photonic technology, other technologies and materials such as plasmonics with graphene respectively, may offer a viable infrastructure solution on existing THz technology challenges. This survey paper is a thorough investigation on the current and beyond state of the art plasmonic system implementation for THz communications, by providing in-depth reference material, highlighting the fundamental aspects of plasmonic technology roles in future THz band wireless communication and THz wireless applications, that will define future demands coping with users’ needs.
关键词： surface plasmon polariton (SPP),wireless NoC (WiNoC),graphennas,multiple-input-multiple-output (MIMO),wireless nanosensor networks (WNSNs),GFET,THz transceiver,graphene based WiNoCs (GWiNoCs)
更新于2025-09-16 10:30:52