Quantum Electronics Research Articles

Deep moiré potentials in twisted transition metal dichalcogenide bilayers

In twisted bilayers of semiconducting transition metal dichalcogenides (TMDs), a combination of structural rippling and electronic coupling gives rise to periodic moir\'e potentials that can confine charged and neutral excitations. Here, we report experimental measurements of the structure and spectroscopic properties of twisted bilayers of WSe2 and MoSe2 in the H-stacking configuration using scanning tunneling microscopy (STM). Our experiments reveal that the moir\'e potential in these bilayers at small angles is unexpectedly large, reaching values of above 300 meV for the valence band and 150 meV for the conduction band - an order of magnitude larger than theoretical estimates based on interlayer coupling alone. We further demonstrate that the moir\'e potential is a non-monotonic function of moir\'e wavelength, reaching a maximum at around a 13nm moir\'e period. This non-monotonicity coincides with a drastic change in the structure of the moir\'e pattern from a continuous variation of stacking order at small moir\'e wavelengths to a one-dimensional soliton dominated structure at large moir\'e wavelengths. We show that the in-plane structure of the moir\'e pattern is captured well by a continuous mechanical relaxation model, and find that the moir\'e structure and internal strain rather than the interlayer coupling is the dominant factor in determining the moir\'e potential. Our results demonstrate the potential of using precision moir\'e structures to create deeply trapped carriers or excitations for quantum electronics and optoelectronics.

Effective medium approximation based interpretation for Mueller matrix spectra of polydimethylsiloxane gratings

Dielectric corrugated gratings are of considerable interest due to their applications in acousto-optics, quantum electronics, integrated optics, spectroscopy, and holography integrated optics. Rigorous coupled-wave analysis has been widely used for the analysis of dielectric gratings. However, this approach is not only time-consuming and computer intensive but it also does not really promote the physical understanding of the origin of the observed optical behavior. Here, we use Mueller matrix (MM) spectroscopic ellipsometry to systematically study the sinusoidal polydimethylsiloxane grating. We correlate the observed polarization mixing in the Mueller matrix to the underlying physical origin using the physics-based approach. The calculated MM contour plots obtained from a biaxial Bruggemann effective medium approximation model are completed by the presence of Rayleigh-Woods anomalies. The roles of optical interference, geometric anisotropy, and diffraction orders are respectively identified by their different dispersion behavior, with their interactions and couplings highlighted. Such a straightforward procedure provides a new method for analyzing dielectric gratings, which requires considerably less computer power and is directly linked to the physical interpretations.

The Role Of Quantum Electronics In Alternative Energy

The article deals with Quantum electronics, as a field of physics that studies methods of amplification and generation of electromagnetic radiation based on the phenomenon of stimulated radiation in nonequilibrium quantum systems, as well as the properties of amplifiers and generators obtained in this way and their application, a description of the structure of the most important lasers is given, physical foundations of quantum electronics, which are reduced primarily to the application of Einstein's theory of radiation to thermodynamically nonequilibrium systems with discrete energy levels. The article is intended for undergraduates of the Department of Physics, Radio Engineering, who have interests in the field of research and applications of laser radiation, and is aimed at giving them the minimum necessary for that initial information on quantum electronics.

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Recent Research and Development Status of Relaxed Optics and Laser Technology: A Review

It is shown that for laser technologies it was necessary to create a new branch of physics: Relaxed Optics (synthesis of methods of the physical optics, quantum electronics, physical chemistry, physics of irreversible phenomena in unitary system). It is allowed to explain complex chain processes of interaction light and matter. Possible applications of Relaxed Optical methods for the modeling of the laser-induced processes phenomena, including laser implantation (surface and subsurface processes), laser-induced optical breakdown (volume processes) and laser annealing of radiation and other defects in solid, are discussed. Perspectives of using these methods for the creation of new laser technologies, including creation new types of optoelectronic devices (heterostructures, diffraction lattices, etc.), resolution the problems of metallurgy, material science, painting, architecture and a building, are analyzed.

Journal of Selected Topics in Quantum Electronics on Lidars and Photonic Radars

Journal of Selected Topics in Quantum Electronics on Lidars and Photonic Radars

IEEE Journal of Selected Topics in Quantum Electronics

IEEE Journal of Selected Topics in Quantum Electronics

Journal of Selected Topics in Quantum Electronics on Semiconductor Lasers

Journal of Selected Topics in Quantum Electronics on Semiconductor Lasers

Journal of Selected Topics in Quantum Electronics on Optical Detectors

Journal of Selected Topics in Quantum Electronics on Optical Detectors

Journal of Selected Topics in Quantum Electronics on Machine Learning in Photonic Communication and Measurement Systems

Journal of Selected Topics in Quantum Electronics on Machine Learning in Photonic Communication and Measurement Systems

Quasi-two-dimensional electron gas at the oxide interfaces for topological quantum physics

The development of “fault-tolerant” quantum computers, unaffected by noise and decoherence, is one of the fundamental challenges in quantum technology. One of the approaches currently followed is the realization of “topologically protected” qubits which make use of quantum systems characterized by a degenerate ground state of composite particles, known as “non-Abelian anyons”, able to encode and manipulate quantum information in a non-local manner. In this paper, we discuss the potential of quasi-two-dimensional electron gas (q2DEG) at the interface between band insulating oxides, like LaAlO3 and SrTiO3, as an innovative technological platform for the realization of topological quantum systems. Being characterized by a unique combination of unconventional spin-orbit coupling, magnetism, and 2D-superconductivity, these systems naturally possess most of the fundamental characteristics needed for the realization of a topological superconductor. These properties can be widely tuned by electric field effect acting on the orbital splitting and occupation of the non-degenerate 3d xy and 3d xz, yz bands. The topological state in oxide q2DEGs quasi-one-dimensional nanochannels could be therefore suitably controlled, leading to conceptual new methods for the realization of a topological quantum electronics based on the tuning of the orbital degrees of freedom.

Distribution of Nitrogen-Vacancy NV– Centers in Cubic Diamond Crystals from Anabar Placers as Revealed By ODMR and PL Tomography

Nitrogen-vacancy NV– centers, which are of considerable interest for quantum electronics, are artificially produced in the diamond structure by irradiation and subsequent annealing. In this work, these centers were revealed in natural diamonds of cubic habit (type IaA + Ib according to physical classification) from an industrial placer deposit of the Anabar River (NE Siberian platform) using the method of optically detected magnetic resonance (ODMR). Localization of the NV– centers in the dislocations slip planes {111}, separated by distances of about 5 μm, was established by means of scanning the ODMR and PL signals with a submicron resolution. In various crystals, one or two intersecting systems of such slip planes have been revealed. The largest amounts of these defects were found in the peripheral zones of crystals containing increased amounts of single isomorphic nitrogen atoms in the structure. The data obtained indicate the formation of the NV– centers in natural diamonds under post-crystallization plastic deformation, i.e., by a mechanism that differs from the widely used method of their artificial production.

IEEE Journal of Selected Topics in Quantum Electronics Topic Codes and Topics

IEEE Journal of Selected Topics in Quantum Electronics Topic Codes and Topics

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Journal of Selected Topics in Quantum Electronics on Hybrid Integration for Silicon Photonics

Localizing Fractional Quasiparticles on Graphene Quantum Hall Antidots

We report localization of fractional quantum Hall (QH) quasiparticles on graphene antidots. By studying coherent tunneling through the localized QH edge modes on the antidot, we measured the QH quasiparticle charges to be approximately ±e/3 at fractional fillings of ν=±1/3. The Dirac spectrum in graphene allows large energy scales and robust quasiparticle localization against thermal excitation. The capability of localizing fractional quasiparticles on QH antidots brings promising opportunities for realizing anyon braiding and novel quantum electronics.

(Invited) Low-Temperature Growth of Strained Germanium Quantum Wells for High Mobility Applications

The extremely high hole mobilities attainable in strained germanium quantum wells (QW) provide a unique pathway to develop novel devices in the emerging field of quantum electronics. A major challenge associated with the growth of Ge QW structures using the industrial standard reduced-pressure chemical vapor deposition (RP-CVD) technique is the incorporation of unintentional impurities in the growing film. We will show that a compromise exists between the growth conditions that minimize the various impurities (mainly O and Si) and the abruptness of the QW. The purity of the incoming gas plays a central role in this compromise and will be discussed.

Stretchable Freestanding Films of 3D Nanocrystalline Blue Phase Elastomer and Their Tunable Applications

AbstractGiven that it is a potential medium for 3D manipulation of photons in the forward‐looking technology of quantum optics, nonlinear optics, electronics, nanomaterials, and bionics, 3D photonic crystal (PhC) is a promising material of strategic significance and has great impact on scientific development. Blue phase (BP), a liquid crystalline mesophase with unique nanoscaled 3D PhC features, has been shown to contain significant potential values in fundamental studies and technological applications. However, thus far, the environmental stability of BP devices remains a puzzling issue of material exploitation. Therefore, in this study, stretching‐tunable BP elastomer (BPE) photonic bandgap (PBG) free‐standing films are fabricated via full photopolymerization. The BPE films exhibit benefit‐specific features, including sharp PBG with high reflectivity and flexible tunability in the visible region, high thermal stability, and good mechanical ductility and resistance in chemicals. These properties are attributed to the pre‐developed, fully‐reactive mesogenic materials employed, which show BP states in a wide temperature range, including room temperature. Additionally, mirrorless laser applications with flexible tunability are also realized in this study. The freestanding BPE film can be used as a prototype instrumentality to promote the future development of multifunctional intelligent applications in lasers, sensors, displays, intelligent lightings, lidars, micro‐robots and antennas.

Predominance of z2-orbitals at the surface of both hole- and electron-doped manganites

The electronic properties of hole- and electron-doped manganites were probed by a combination of x-ray absorption and photoemission spectroscopies. Hole-doped La0.7Ba0.3MnO3 and electron-doped La0.7Ce0.3MnO3 thin films were epitaxially grown on SrTiO3 substrates by means of pulsed laser deposition. Ex-situ x-ray diffraction demonstrated the substrate/film epitaxy relation and in-situ low energy electron diffraction provided evidence of high structural order of film surfaces. By combining synchrotron x-ray absorption and x-ray photoemission spectroscopy, evidence of Mn ions into a 2+ state as a result of the Ce4+ substitution in the electron-doped manganites was provided. Angular resolved photo-emission spectroscopy (ARPES) results showed a predominance of z2-orbitals at the surface of both hole- and, unexpectedly, electron-doped manganites thus questioning the validity of the commonly accepted scenario describing the electron filling in manganites’ 3d orbitals in oxide manganites. The precise determination of the electronic and orbital properties of the terminating layers of oxide manganites paves the way for engineering multi-layered heterostructures thus leading to novel opportunities in the field of quantum electronics.

Call for papers: Announcing an issue of the IEEE Journal of Selected Topics in Quantum Electronics on hybrid integration for silicon photonics

Call for papers: Announcing an issue of the IEEE Journal of Selected Topics in Quantum Electronics on hybrid integration for silicon photonics