Harvey E. Beere
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View article: Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials
Achieving 100% amplitude modulation depth in the terahertz range with graphene-based tuneable capacitance metamaterials Open
Effective control of terahertz radiation requires fast and efficient modulators with a large modulation depth—a challenge that is often tackled by using metamaterials. Metamaterial-based active modulators can be created by placing graphene…
View article: Landau level single-electron pumping
Landau level single-electron pumping Open
We present a detailed study of the effect of a strong perpendicular magnetic field on single-electron pumping in a device utilising a finger-gate split-gate configuration, characterised by high pumping precision. In the quantum Hall regime…
View article: Free-space and polarization maintaining delivery of terahertz radiation from a quantum cascade laser in a dry dilution refrigerator
Free-space and polarization maintaining delivery of terahertz radiation from a quantum cascade laser in a dry dilution refrigerator Open
We demonstrate a free-space terahertz (THz) optical system inside a dry dilution refrigerator that allows us to direct polarized THz radiation from a quantum cascade laser (QCL) to a sample held at a base temperature of 28 mK. The sample t…
View article: Preserving Coulomb blockade in transport spectroscopy of quantum dots, by dynamical tunnel-barrier compensation
Preserving Coulomb blockade in transport spectroscopy of quantum dots, by dynamical tunnel-barrier compensation Open
Surface-gated quantum dots (QDs) in semiconductor heterostructures represent a highly attractive platform for quantum computation and simulation. However, in this implementation, the barriers through which the QD is tunnel-coupled to sourc…
View article: Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using cryogenic on-chip multiplexing
Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using cryogenic on-chip multiplexing Open
The mass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator. It is, therefore, beneficial to…
View article: Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using millikelvin cryogenic on-chip multiplexing
Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using millikelvin cryogenic on-chip multiplexing Open
The mass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator. It is, therefore, beneficial to…
View article: Effects of phosphorous and antimony doping on thin Ge layers grown on Si
Effects of phosphorous and antimony doping on thin Ge layers grown on Si Open
Suppression of threading dislocations (TDs) in thin germanium (Ge) layers grown on silicon (Si) substrates has been critical for realizing high-performance Si-based optoelectronic and electronic devices. An advanced growth strategy is desi…
View article: Comparative study of low magnetic field effects in finger-finger and finger-split gate single electron pumps
Comparative study of low magnetic field effects in finger-finger and finger-split gate single electron pumps Open
Single Electron Pump (SEP) devices that can deliver single electrons at high frequencies are fabricated using two different gate geometries. The pump quantum dot (QD) can be defined either using two finger gates where the pump operates in …
View article: Low frequency resistance fluctuations in an ionic liquid gated channel probed by cross-correlation noise spectroscopy
Low frequency resistance fluctuations in an ionic liquid gated channel probed by cross-correlation noise spectroscopy Open
A system in equilibrium keeps ``exploring" nearby states in the phase space and consequently, fluctuations can contain information, that the mean value does not. However, such measurements involve a fairly complex interplay of effects aris…
View article: Photoelectric tunable-step terahertz detectors: a study on optimal antenna parameters, speed, and temperature performance
Photoelectric tunable-step terahertz detectors: a study on optimal antenna parameters, speed, and temperature performance Open
Field effect transistors have shown promising performance as terahertz (THz) detectors over the past few decades. Recently, a quantum phenomenon, the in-plane photoelectric effect, was discovered as a novel detection mechanism in gated two…
View article: Effects of phosphorous and antimony doping on thin Ge layers grown on Si
Effects of phosphorous and antimony doping on thin Ge layers grown on Si Open
Suppression of threading dislocations (TDs) in thin germanium (Ge) layers grown on silicon (Si) substrates has been critical for realizing high-performance Si-based optoelectronic and electronic devices. An advanced growth strategy is desi…
View article: Achieving 100% amplitude modulation depth in a graphene-based tuneable capacitance metamaterial
Achieving 100% amplitude modulation depth in a graphene-based tuneable capacitance metamaterial Open
Effective control of terahertz radiation requires the development of efficient and fast modulators with a large modulation depth. This challenge is often tackled by using metamaterials, artificial sub-wavelength optical structures engineer…
View article: Multiple electron pumping
Multiple electron pumping Open
View article: Enhanced Delivery and Detection of Terahertz Frequency Radiation from a Quantum Cascade Laser Within Dilution Refrigerator
Enhanced Delivery and Detection of Terahertz Frequency Radiation from a Quantum Cascade Laser Within Dilution Refrigerator Open
We report on significant enhancements to the integration of terahertz (THz) quantum cascade lasers (QCL) and THz detection with a two-dimensional electron gas (2DEG) within a dilution refrigerator obtained by the inclusion of a multi-mesh …
View article: Cylindrical Multimode Waveguides as Focusing Interferometric Systems
Cylindrical Multimode Waveguides as Focusing Interferometric Systems Open
Delivery and focusing of radiation requires a variety of optical elements such as waveguides and mirrors or lenses. Heretofore, they were used separately, the former for radiation delivery, the latter for focusing. Here, we show that cylin…
View article: Real-Time Measure of the Lattice Temperature of a Semiconductor Heterostructure Laser via an On-Chip Integrated Graphene Thermometer
Real-Time Measure of the Lattice Temperature of a Semiconductor Heterostructure Laser via an On-Chip Integrated Graphene Thermometer Open
The on-chip integration of two-dimensional nanomaterials, having exceptional optical, electrical, and thermal properties, with terahertz (THz) quantum cascade lasers (QCLs) has recently led to wide spectral tuning, nonlinear high-harmonic …
View article: Versatile and active THz wave polarization modulators using metamaterial/graphene resonators
Versatile and active THz wave polarization modulators using metamaterial/graphene resonators Open
Active modification of the polarization state is a key feature for the next-generation of wireless communications, sensing, and imaging in the THz band. The polarization modulation performance of an integrated metamaterial/graphene device …
View article: Self‐Induced Mode‐Locking in Electrically Pumped Far‐Infrared Random Lasers
Self‐Induced Mode‐Locking in Electrically Pumped Far‐Infrared Random Lasers Open
Mode locking, the self‐starting synchronous oscillation of electromagnetic modes in a laser cavity, is the primary way to generate ultrashort light pulses. In random lasers, without a cavity, mode‐locking, the nonlinear coupling amongst lo…
View article: Directed delivery of terahertz frequency radiation from quantum cascade lasers within a dry 3He dilution refrigerator
Directed delivery of terahertz frequency radiation from quantum cascade lasers within a dry 3He dilution refrigerator Open
We present a scheme for the full integration of terahertz (THz) frequency quantum cascade lasers (QCLs) within a dilution refrigerator in order to provide a directed delivery of THz power into the sample space. We describe a successful ope…
View article: Ultrafast modulation of a THz metamaterial/graphene array integrated device
Ultrafast modulation of a THz metamaterial/graphene array integrated device Open
We report on the ultrafast modulation of a graphene loaded artificial metasurface realized on a SiO2/Si substrate by near-IR laser pump, detected via terahertz probe at the resonant frequency of ∼0.8 THz. The results have been acquired by …
View article: Theory of the in-plane photoelectric effect in two-dimensional electron systems
Theory of the in-plane photoelectric effect in two-dimensional electron systems Open
A new photoelectric phenomenon, the in-plane photoelectric (IPPE) effect, has\nbeen recently discovered at terahertz (THz) frequencies in a\nGaAs/Al$_x$Ga$_{1-x}$As heterostructure with a two-dimensional (2D) electron\ngas (W. Michailow et…
View article: Terahertz Metamaterial Optoelectronic Modulators With GHz Reconfiguration Speed
Terahertz Metamaterial Optoelectronic Modulators With GHz Reconfiguration Speed Open
All-electronic ultrafast control of terahertz radiation is demonstrated in integrated metamaterial/graphene devices. By electrostatic gating the graphene conductivity, the overall optical response of the incident terahertz E-field is modif…
View article: An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection
An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection Open
Many mid- and far-infrared semiconductor photodetectors rely on a photonic response, when the photon energy is large enough to excite and extract electrons due to optical transitions. Toward the terahertz range with photon energies of a fe…
View article: Effects of biased and unbiased illuminations on two-dimensional electron gases in dopant-free GaAs/AlGaAs
Effects of biased and unbiased illuminations on two-dimensional electron gases in dopant-free GaAs/AlGaAs Open
Illumination is performed at low temperature on dopant-free two-dimensional electron gases (2DEGs) of varying depths, under unbiased (gates grounded) and biased (gates at a positive or negative voltage) conditions. Unbiased illuminations i…
View article: Giant Magnetoresistance in a Chemical Vapor Deposition Graphene Constriction
Giant Magnetoresistance in a Chemical Vapor Deposition Graphene Constriction Open
Magnetic field-driven insulating states in graphene are associated with samples of very high quality. Here, this state is shown to exist in monolayer graphene grown by chemical vapor deposition (CVD) and wet transferred on Al2O<…
View article: Electrically Controllable Kondo Correlation in Spin-Orbit-Coupled Quantum Point Contacts
Electrically Controllable Kondo Correlation in Spin-Orbit-Coupled Quantum Point Contacts Open
Integrating the Kondo correlation and spin-orbit interactions, each of which have individually offered unprecedented means to manipulate electron spins, in a controllable way can open up new possibilities for spintronics. We demonstrate el…
View article: Active Terahertz Modulator and Slow Light Metamaterial Devices with Hybrid Graphene–Superconductor Photonic Integrated Circuits
Active Terahertz Modulator and Slow Light Metamaterial Devices with Hybrid Graphene–Superconductor Photonic Integrated Circuits Open
Metamaterial photonic integrated circuits with arrays of hybrid graphene–superconductor coupled split-ring resonators (SRR) capable of modulating and slowing down terahertz (THz) light are introduced and proposed. The hybrid device’s optic…
View article: Active Terahertz Modulator and Slow Light Metamaterial Devices with Hybrid Graphene–Superconductor Photonic Integrated Circuits
Active Terahertz Modulator and Slow Light Metamaterial Devices with Hybrid Graphene–Superconductor Photonic Integrated Circuits Open
Metamaterial photonic integrated circuits with arrays of hybrid graphene–superconductor coupled split-ring resonators (SRR) capable of modulating and slowing down terahertz (THz) light are introduced and proposed. The hybrid device’s optic…
View article: Theory of the in-plane photoelectric effect in a two-dimensional electron system
Theory of the in-plane photoelectric effect in a two-dimensional electron system Open
A new photoelectric phenomenon, the in-plane photoelectric (IPPE) effect, has been recently discovered at terahertz (THz) frequencies in a GaAs/Al$_x$Ga$_{1-x}$As heterostructure with a two-dimensional (2D) electron gas (W. Michailow et al…
View article: Single-electron pump with highly controllable plateaus
Single-electron pump with highly controllable plateaus Open
Future quantum based electronic systems will demand robust and highly accurate on-demand sources of current. The ultimate limit of quantized current sources is a highly controllable device that manipulates individual electrons. We present …