A5100405983- Gyrotron and Vacuum Electronics Research
- Microwave Engineering and Waveguides
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Pulsed Power Technology Applications
- Particle accelerators and beam dynamics
- Atmospheric Ozone and Climate
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Plasma Diagnostics and Applications
- Orbital Angular Momentum in Optics
- Radio Astronomy Observations and Technology
- Photonic and Optical Devices
- Photonic Crystals and Applications
- Wireless Body Area Networks
- Laser Design and Applications
- stochastic dynamics and bifurcation
- Atmospheric chemistry and aerosols
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Electrostatic Discharge in Electronics
- Nanofabrication and Lithography Techniques
- Advanced Antenna and Metasurface Technologies
- Nonlinear Photonic Systems
Queen Mary University of London
2005-2024
University of California, Riverside
2024
Chongqing University
2024
Southeast University
2023
The University of Tokyo
2020-2021
Guiyang University
2019-2021
University of Notre Dame
2020
Leiden University
2020
Cardiff University
2007-2011
Centre National de la Recherche Scientifique
2009
ABSTRACT The recent detection of ethanolamine (EtA, HOCH$_2$CH$_2$NH$_2$), a key component phospholipids, i.e. the building blocks cell membranes, in interstellar medium is line with an exogenous origin life-relevant molecules. However, stability and survivability EtA molecules under inter/circumstellar Solar System conditions have yet to be demonstrated. Starting from assumption that mainly forms on ice grains, we systematically exposed EtA, pure mixed amorphous water (H$_2$O) ice,...
We investigate both analytically and numerically the propagation dynamic of on-axis off-axis cosine-Gaussian (CG) beams in a linear medium with quadratic external potential. CG beam evolves periodically period depended on potential depth ( α ) whether shape is symmetrical respect to optical axis. In each period, first splits into two sub-beams different accelerated direction; they then reverse direction owing finally merge again reproduce its initial shape, whole process repeats...
A compact high-power extended interaction oscillator (EIO) driven by a pseudospark-sourced (PS-sourced) sheet electron beam (SEB) is presented at 0.35 THz. It combines the advantages of planar circuit and SEB generated from PS discharge, including large cross-section, high gain per unit length, current density with additional benefit not requiring an external focusing magnetic field. Staying within what achievable microfabrication techniques, influence tolerance on Q value, resonance...
The development of communication devices, especially cellular phones has necessitated the advances several portable and wearable technologies, such as Bluetooth headsets within wireless body area networks (WBAN). Such devices use human a channel; hence, comprehensive understanding transmission mechanism between is vital. This study presents an investigative to characterise electromagnetic body-mounted headset antenna mobile phone handset antenna. Commercially used antennas have been various...
Solid-phase photo-processes involving icy dust grains greatly affect the chemical evolution of interstellar medium by leading to formation complex organic molecules and inducing photodesorption. So far, focus laboratory studies has been mainly on impact energetic ultraviolet (UV) photons ices, but direct vibrational excitation infrared (IR) is expected influence morphology content ices as well. However, little still known about mechanisms through which this excess energy dissipated, its...
Abstract A pseudospark (PS) discharge can generate an electron beam with a high current density. The be self-focused by ion channel and transported over long distance without the need for external magnetic field. Such features make it attractive to drive millimeter-wave/THz interaction circuits generation of high-power radiation from compact device. This paper presents experimental results on transportation PS-sourced different cross-sections, as well differences post acceleration. Its...
A backward wave oscillator (BWO) based on a double-staggered grating (DSG) slow structure (SWS) is investigated as high-power wideband terahertz (THz) source, driven by sheet electron beam emitting from pseudospark plasma cathode. First, the DSG SWS optimized in simulation to have suitable dispersion characteristic. Then, BWO with output consisting of tapered section and an L-shaped connector modeled under operating voltage 24-38 kV current density 2-5× 10 <sup...
We review recent suggestions to quantum simulate scalar electrodynamics (the lattice Abelian Higgs model) in 1+1 dimensions with rectangular arrays of Rydberg atoms. show that platforms made publicly available recently allow empirical explorations the critical behavior simulators. discuss progress regarding phase diagram two-leg ladders, effective Hamiltonian approaches and construction hybrid algorithms targeting hadronization collider physics event generators.
Using the density matrix renormalization group algorithm, we map ground-state phase diagram of a two-leg Rydberg ladder array with lattice spacings $a_x=2a_y$. We identify various wave phases that spontaneously break translational symmetry or top-bottom reflection within ladder. By increasing laser detuning from zero, where system is in disordered preserves all symmetries, observe orders spontaneous breaking $\mathbb{Z}_p$ symmetries at intermediate values, while preserved. These exhibit...
In this article, the characteristics of pseudospark (PS) discharge were studied through particle-in-cell simulations with consideration external circuit. The different stages, including Townsend discharge, hollow cathode and super-dense glow, characterized by voltage current. sources electrons at stages analyzed, generated from ionization background gas playing dominant role. electron densities glow in range 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...
The Lumped Element Kinetic Inductance Detector (LEKID) is a single layer superconducting detector which provides simple and elegant solution for producing large format, multiplexed arrays of background limited detectors ground based astronomy. LEKID design incorporates both the detecting element absorber an array pixel does not require feed‐horns or antennas to couple in light from telescope. In order achieve good optical efficiency across atmospheric window, geometry material choice need...
A novel double nonparallel staggered grating (DNPSG) slow wave structure (SWS) is proposed to enhance the coupling impedance in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}$ </tex-math></inline-formula> -band backward oscillator (BWO) driven by pseudospark-sourced sheet electron beam. The DNPSG SWS has been shown broadband of 72–125 GHz and higher compared with traditional (DSG) simulation. BWO...
In general, a dual-input Fourier transform spectrometer (FTS) produces interferograms that have components of both even and odd symmetry. addition to the desired interferogram contribution due source under study, which has symmetry, each FTS output is often found exhibit component symmetry arises from fact beam splitter not ideal. Additionally, itself can be emission modulated signal at interferometer. An exploration effects, correction, nonideal beam-splitter characteristics in presented,...
SCExAO at the Subaru telescope is a visible and near-infrared high-contrast imaging instrument employing extreme adaptive optics coronagraphy. The feeds light (JHK) to integral field spectrograph CHARIS. Recently, Wollaston prism was added CHARIS' optical path, giving CHARIS spectropolarimetric capability that unique among instruments. We present comprehensive detailed Mueller matrix model describing instrumental polarization effects of complete thus instrument, using measurements with...
Polarization Differential Imaging (PDI) is one of the most productive modes current high-contrast imagers. Dozens new protoplanetary, transition and debris disks were imaged recently for first time, helping us understand processes planet formation, giving clues on mass potential planets inside these disks, even if they cannot be directly. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument equipped with a fast visible dual-camera polarimetric module, VAMPIRES, already...
We describe the objectives, design and predicted performance of Clover, which is a ground-based experiment to measure faint ``B-mode'' polarisation pattern in cosmic microwave background (CMB). To achieve this goal, clover will make polarimetric observations approximately 1000 deg^2 sky spectral bands centred on 97, 150 225 GHz. The be made with two-mirror compact range antenna fed by profiled corrugated horns. telescope beam sizes for each band are 7.5, 5.5 arcmin, respectively. measured...
This paper presents the design of an ortho-mode transducer (OMT) to separate two orthogonal linearly polarized signals traveling in a circular waveguide with frequency channels at 150/255 GHz band. Simulations (in HFSS) are presented determine optimal probe geometry and feed impedance achieve good coupling optimized probes over wide bandwidth corresponding impedances for telescopes operating 150 225 GHz. The results show that band, return loss can reach below -20 dB from 126 180 cross...
A W-band rising-sun spatial harmonic magnetron (SHM) has been designed to generate high-power millimetre wave. The consists of 24 side cavities and a novel axial output structure, operating at π mode. Particle-in-cell (PIC) simulation results show that the could produce maximum power 427 kW with an operation efficiency 90.4% 94.5 GHz, under anode voltage 31.5 kV magnetic field 1.15 T. system is also uniform 1.15-T in interaction space magnetron.
This paper presents a system requirement analysis of multi-beam laser interference nanolithography for nanoscale structuring materials including seven sections: introduction, formation patterns, user requirements, architecture, experiments, discussions and conclusions. Analytical expressions were obtained the spatial distribution radiation interfering beams as function their amplitudes, phases, angles incidence on sample, polarization planes with computer simulation experimental results. The...
To provide high-power microwave for the heating and current drive (HCD) in UK fusion power programme Spherical Tokamak Energy Production (STEP), we have designed a W-band spatial harmonic magnetron (SHM) as millimeter wave source. The has 24 side cavities (rising-sun structure) novel axial output structure consisting of funnel connected with circular waveguide. Particle-in-cell (PIC) simulation results show that could operate at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML"...
SCExAO at the Subaru telescope is a visible and near-infrared high-contrast imaging instrument employing extreme adaptive optics coronagraphy.The feeds light (JHK) to integralfield spectrograph CHARIS.The spectropolarimetric capability of CHARIS enabled by Wollaston prism unique among imagers.We present detailed Mueller matrix model describing instrumental polarization effects complete optical path, thus instrument.From measurements with internal source, we find that image derotator...
We have designed a dual-band backward wave oscillator (BWO) using double staggered grating (DSG) slow-wave structure (SWS) and pseudospark-sourced sheet electron beam. In the simulation of high-frequency characteristics, DSG SWS has been shown wide operating band 72–125 GHz high coupling impedance. The complete BWO consists 10 units, together with wideband output structure. cold-test BWO, transmission is greater than −7 dB in 74–100 GHz, 109–125 GHz. hot-test performance analysed by...