A5016384022- Spectroscopy and Laser Applications
- Terahertz technology and applications
- Photonic and Optical Devices
- Topological Materials and Phenomena
- 2D Materials and Applications
- Plasmonic and Surface Plasmon Research
- Perovskite Materials and Applications
- Metamaterials and Metasurfaces Applications
- Atmospheric Ozone and Climate
- Semiconductor Lasers and Optical Devices
- Quantum and electron transport phenomena
- Multiferroics and related materials
- GaN-based semiconductor devices and materials
- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Photonic Crystals and Applications
- Advanced Semiconductor Detectors and Materials
- Physics of Superconductivity and Magnetism
- Photoreceptor and optogenetics research
- Molecular Sensors and Ion Detection
- Mechanical and Optical Resonators
- Microwave Dielectric Ceramics Synthesis
- Semiconductor Quantum Structures and Devices
- Luminescence and Fluorescent Materials
- Quantum Dots Synthesis And Properties
University of Cambridge
2014-2022
Nagoya University
2018
Tohoku University
2018
The University of Tokyo
2018
Osaka University
2018
Kyoto University
2018
Low-bandgap CH3 NH3 (Pbx Sn1-x )I3 (0 ≤ x 1) hybrid perovskites (e.g., ≈1.5-1.1 eV) demonstrating high surface coverage and superior optoelectronic properties are fabricated. State-of-the-art photovoltaic (PV) performance is reported with power conversion efficiencies approaching 10% in planar heterojunction architecture small (<450 meV) energy loss compared to the bandgap (>100 cm2 V-1 s-1 ) intrinsic carrier mobilities.
Hysteresis-free operational stable perovskite FETs is demonstrated through ionic passivation and crystal modification.
Abstract Optoelectronic terahertz modulators, operated by actively tuning metamaterial, plasmonic resonator structures, have helped to unlock a myriad of applications, ranging from spectroscopy and imaging communications. At the same time, due inherently versatile dispersion properties metamaterials, they offer unique platforms for studying intriguing phenomena such as negative refractive index slow light. Active resonance frequency metamaterial working in regime is achieved integrating...
We demonstrate how terahertz time-domain spectroscopy (THz-TDS) operating in reflection geometry can be used for quantitative conductivity mapping of large area chemical vapour deposited graphene films on sapphire, silicon dioxide/silicon and germanium. validate the technique against measurements performed with previously established conventional transmission based THz-TDS are able to resolve changes response induced back-gate voltages. Compared geometry, measurement mode requires careful...
We report the fast amplitude modulation of a quantum cascade laser emitting in single-mode operation terahertz frequency range by employing compact, integrated devices based on interplay between plasmonic antenna arrays and monolayer graphene. By acting carrier concentration graphene, optical response these resonances was modified. The modulator's characteristics have been studied using both time domain spectroscopic systems, yielding broad resonant arrays, lasers, providing us with narrow...
Strong spin–momentum coupling in topological insulators gives rise to surface states, protected against disorder scattering by time reversal symmetry. The study of these exotic quantum states not only provides an opportunity explore fundamental phenomenon condensed matter physics, such as the spin Hall effect, but also lays foundation for applications computing spintronics. Conventional electrical measurements suffer from substantial bulk interference, making it difficult clearly identify...
Active control of the amplitude and frequency terahertz sources is an essential prerequisite for exploiting a myriad applications in imaging, spectroscopy, communications. Here we present optoelectronic, external modulation technique applied to quantum cascade laser which holds promise addressing number important challenges this research area. A hybrid metamaterial/graphene device implemented into cavity set-up allowing optoelectronic tuning feedback laser. We demonstrate powerful,...
RD, HEB and DAR acknowledge financial support from the Engineering Physical Sciences Research Council (Grant No. EP/J017671/1, Coherent Terahertz Systems). SH acknowledges funding EPSRC EP/K016636/1, GRAPHTED). KN University of Cambridge Nanoscience Doctoral Training Centre (EPSRC EP/G037221/1) for support.
A terahertz (THz) optical amplifier based on a 2.9 THz quantum cascade laser (QCL) structure has been demonstrated. By depositing an antireflective coating the QCL facet, mirror losses are enhanced to fully suppress lasing action, creating (QC) amplifier. Terahertz radiation amplification obtained, by coupling separate multi-mode of same active region design QC bare cavity gain is achieved and shows excellent agreement with spectrum from original without coating. Furthermore, maximum ∼30 dB...
Abstract Ferromagnetic ordering in a topological insulator can break time-reversal symmetry, realizing dissipationless electronic states the absence of magnetic field. The control state is great importance for future device applications. We provide detailed systematic study highly doped Cr x Sb 2−x Te 3 thin films using electrical transport, magneto-optic Kerr effect measurements and terahertz time domain spectroscopy, also report an efficient electric gating ferromagnetic order electrolyte...
Porous GaN distributed Bragg reflectors offer an opportunity to provide the high reflectance, lattice-matched components required for efficient vertical cavity surface emitting lasers. The birefringence of these structures is, therefore, key interest as it could be used control polarization emitted light. Here, we present a detailed analysis optical both laterally etched, patterned and self-assembled radial porous structures. We correlate this with 3D structure pores, which measure through...
Photonic crystals (PhCs) possess outstanding optical properties that can be exploited for chemical sensing. We utilized a three-dimensional close-packed PhC structure made of functionalized silica nanoparticles. They consist alternating high and low refractive index regions have properties, such as photonic band structures, are very sensitive to the change physical structures. This study used 2,4,6-trinitrotoluene (TNT) illustrate detection method based on transmissive edge shift (TPBES) due...
Mercury exposure constitutes an acute risk to human health and the environment. Driven by requirement monitor trace-level mercury, we report a highly sensitive mercury(II) DNA sensor enhanced silver(I) activation, followed mercury(II)-specific oligonucleotides (MSO) molecular configuration switch mercury(II)-modulated FRET. Activating MSO strands with silver(I), mismatched cytosine–silver(I)–cytosine bridges induce individual fold readily in response resulting fluorescence signal. The...
The growing interest in terahertz (THz) technologies recent years has seen a wide range of demonstrated applications, spanning from security screening, non-destructive testing, gas sensing, to biomedical imaging and communication. Communication with THz radiation offers the advantage much higher bandwidths than currently available, an unallocated spectrum. For this be realized, optoelectronic components capable manipulating at high speeds signal-to-noise ratios must developed. In work we...
We analyze in-plane and out-of-plane texture terahertz analysis of a YBa2Cu3O7-δ (YBCO) film deposited by chemical solution deposition technique onto LaAlO3 (100) substrate. X-ray diffraction reveals the presence (00l) reflections for YBCO phase. The texture, measured rocking curve, shows two sub-layers with Δω = 0.45° 1.8°. value c-axis fraction crystallites is 81%. Also, was studied ϕ-scan measurements (102) reflection, displaying mostly colony oriented grains, colonies a-axis grains...
Summary form only given. The continuous development of terahertz (THz) sources has opened up many potential applications in spectroscopy, imaging and communications. One popular THz source is the quantum cascade laser (QCL), which desirable properties including compactness high output power with a narrow emission frequency. For such to be successfully integrated into communication system, it necessary have control over amplitude, frequency phase. wireless purposes, amplitude modulators must...
We report the characterization of centimeter sized graphene field-effect transistors with ionic gating which enables active frequency and amplitude modulation terahertz (THz) radiation. Chemical vapour deposited different grain sizes were studied using THz time-domain spectroscopy. demonstrate that plasmonic resonances intrinsic to can be tuned over a wide range frequencies by engineering size graphene. Further tuning resonance, up ~65 GHz, is achieved electrostatic doping via gating. These...
ADVERTISEMENT RETURN TO ISSUEPREVAdditions and Correc...Additions CorrectionsNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to Fast Modulation of Terahertz Quantum Cascade Lasers Using Graphene Loaded Plasmonic AntennasRiccardo Degl'Innocenti*, David S. Jessop, Christian W. O. Sol, Long Xiao, Stephen J. Kindness, Hungyen Lin, Axel Zeitler, Philipp Braeuninger-Weimer, Stephan Hofmann, Yuan Ren, Varun Kamboj, Jonathan P. Griffiths, Harvey E. Beere, A. RitchieCite this: ACS Photonics...
We have measured the terahertz (THz) conductance of a 23 quintuple layer thick film bismuth selenide (Bi<sub>2</sub>Se<sub>3</sub>) and found signatures for topological surface states (TSSs) below 50 K. provide evidence phase transition as function lattice temperature by optical means. In this work, we used THz time-domain spectroscopy (THz-TDS) to measure Bi<sub>2</sub>Se<sub>3</sub>, revealing metallic behavior at temperatures Bi<sub>2</sub>Se<sub>3</sub> 10 e<sup>2</sup>/h 4 K, indicative...