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Design of high-performance and tunable magneto-optical isolators for He–Ne laser
摘要： Herein, we report on high-performance magnetophotonic crystal (MPC) structures, which can be adjusted to create perfect magneto-optical isolators (MOIs) for helium–neon lasers operating at a wavelength of 632.8 nm. The adjustment is carried out by tuning the applied magnetic field to use the high potential of the CeF3 as a new and transparent visible Faraday rotator. For practical purposes, to avoid instabilities due to wavelength fluctuations, we show that achieving a suitable tunable MOI with a flat-top response is possible when the appropriate MPC design is approached.
关键词： wavelength 632.8 nm,magneto-optical isolator,He–Ne laser,magnetic field tunability
更新于2025-09-11 14:15:04
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Path-integral Monte Carlo study of electronic states in quantum dots in an external magnetic field
摘要： We explore the correlated electron states in harmonically confined few-electron quantum dots in an external magnetic field by the path-integral Monte Carlo method for a wide range of the field and the Coulomb interaction strength. Using the phase structure of a preceding unrestricted Hartree-Fock calculation for phase fixing, we find a rich variety of correlated states, often completely different from the prediction of mean-field theory. These are finite temperature results, but sometimes the correlations saturate with decreasing temperature, providing insight into the ground-state properties.
关键词： magnetic field,electron correlations,Hartree-Fock,quantum dots,path-integral Monte Carlo
更新于2025-09-11 14:15:04
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Femtosecond Laser Micromachining of Fabry-Pérot Interferometers for Magnetic Field Sensing
摘要： Fs-laser micromachining is a high precision fabrication technique that can be used to write novel three-dimensional structures, depending on the nature of light-matter interaction. In fused silica, the material modification can lead to (i) an increase of the refractive index around the focal volume, resulting in the formation of optical circuits, or (ii) an enhancement of the etch rate of the laser-affected zones relative to the pristine material, leading to a selective and anisotropic etching reaction that enables fabrication of microfluidic systems. Here, both effects are combined to fabricate a Fabry-Pérot interferometer, where optical waveguides and microfluidic channels are integrated monolithically in a fused silica chip. By filling the channel with a magnetic fluid whose refractive index changes with an external magnetic field, the device can be used as a magnetic field sensor. A linear sensitivity of -0.12 nm/mT is obtained in the 5.0±0.5 to 33.0±0.5 mT range, with the field being applied parallel to the light propagation direction.
关键词： Magnetic Field Sensing,Optofluidic Sensor,Femtosecond Laser Micromachining,Ferrofluids,Fabry-Pérot Interferometers
更新于2025-09-11 14:15:04
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Tunable enhanced sensing of ferrite film using meander-shaped spoof surface plasmon polariton waveguide
摘要： In this letter, the magnetic field enhancement characteristics of the spoof surface plasmon polaritons (SSPPs) is utilized to enhance the sensing of thin ferrite film. The operating sensing frequency can be tuned by adjusting the bias static magnetic field. For demonstration, a magnetic yttrium iron garnet film (i.e., YIG) with small thickness of 2 μm over a simple SSPP-based sensing structure is designed, fabricated and measured, showing improvement of higher than 20 dB to the absorption (i.e., sensing ability). The proposed method has significant potentials in the application of plasmonic integrated devices using thin ferrite materials.
关键词： sensing,magnetic field enhancement,spoof surface plasmon polaritons,ferrite film,SSPPs
更新于2025-09-11 14:15:04
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Triplet exciton fine structure in Pt-rich polymers studied by circularly polarized emission under high magnetic field
摘要： Incorporating heavy atoms into polymer chains represents an effective way to generate emissive triplets. Here we used magneto-optical emission spectroscopy up to 17.5 Tesla for studying the fine structure of the triplet exciton in a series of Pt-rich π-conjugated polymers with various intrachain Pt concentrations. We found that their phosphorescence emission band shows substantial field-induced circular polarization (FICPO) up to 50% with an unusual, nonmonotonic field dependence at cryogenic temperature. From the field-induced energy splitting between left and right circularly polarized phosphorescence we obtained the effective g factor of triplet exciton varying in the range of ?0.13-0.85, which depends on the Pt concentration in the polymer chains. The FICPO of triplet emission originates from the population difference in spin sublevels, which is determined by thermal equilibrium subjected to spin-orbit coupling (SOC), exchange, and Zeeman interactions. Surprisingly we also observed FICPO in the fluorescence emission that results from the singlet-triplet interaction caused by the strong SOC. From these results we extracted the various interaction parameters that describe the exciton fine structure in these Pt-contained compounds.
关键词： Pt-rich polymers,high magnetic field,circularly polarized emission,spin-orbit coupling,triplet exciton
更新于2025-09-11 14:15:04
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Dark exciton brightening and its engaged valley dynamics in monolayer
摘要： We theoretically investigate the valley Zeeman splitting, dark-exciton brightening, and magnetic-field-controlled dark-exciton engaged valley dynamics in monolayer WSe2 subjected to a tilted magnetic field B. In Faraday geometry (out-of-plane B⊥), only bright-exciton emissions emerge, and the valley polarization (VP) as a function of B⊥ for σ + and σ ? circularly polarized laser excitations features an “X” pattern, i.e., the VP is locked to the valley. We also find that the photoluminescence (PL) intensity exhibits a similar behavior to VP. In the Voigt geometry (in-plane B(cid:3)), however, aside from the bright-exciton emission, the dark exciton becomes brightening. The PL intensity of the dark exciton is enhanced parabolically with increasing B(cid:3), independent of the pumping laser helicity. For B along any other direction, as B increases, the dark-exciton emission intensity increases but depends on the pumping laser helicity, accompanied by an decrease of its VP. Furthermore, not only the bright-exciton but also the dark-exciton emission peak splits for laser excitation with different circular polarizations. In addition, the latter demonstrates a much larger peak splitting than the former, which facilitates individual manipulation of each of the two valleys. Our theory paves the way for a study of the properties of bright-dark hybrid states with lifetime orders of magnitude longer than that of the bright states, which is desirable for fields of either spintronics or valleytronics (or their combination).
关键词： monolayer WSe2,dark-exciton brightening,tilted magnetic field,valley dynamics,valley Zeeman splitting
更新于2025-09-11 14:15:04
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Specific Features of Obtaining of Metal Nanowires by Replication of Pores of Track Etched Membranes
摘要： Ensembles (massives) of metal nanowires (with diameters 50-200 nm) were obtained using method of template synthesis. Polymer track etched matrixes were used as template. Nanowires obtained were the replicas of the pores in these membranes. The problems of choosing of electrolyte and different regimes of electrodeposition were discussed. Different techniques of separation of obtained nanowires from growth polymer matrix were used- etching at elevated temperature, ultrasound and UV-treatment. The regimes of obtaining of layer Cu/Ni nanowires were investigated and the optimal voltages were found: 0.8 V for Cu-layer and 1.8 for Ni layer. It was also found that application of magnetic field accelerate the process of electrodeposition; moreover, application of SOUTH pole leads to formation of hollow Ni-layers. Using of “two-bath” method of electrodeposition found to be optimal for obtaining of two-parts wires. Such wires could be used for generation of THz irradiation.
关键词： electrodeposition,effect of magnetic field,track etched membranes,nanowires,matrix synthesis
更新于2025-09-10 09:29:36
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Photonic Microcavity-Enhanced Magnetic Plasmon Resonance of Metamaterials for Sensing Applications
摘要： We investigate photonic microcavity-enhanced magnetic plasmon (MP) resonance in metamaterials for high-quality refractive index sensing. The metamaterials are consisting of a top periodic array of U-shaped metallic split-ring resonators (SRRs), a middle dielectric layer, and a bottom metallic backed plate. The top metallic SRRs that are placed at about Bragg distance above the bottom metallic plate constitute a photonic microcavity. Because the MP resonance excited in metallic SRRs is coupled to the photonic microcavity mode supported by the photonic microcavity, the radiative damping of the MP resonance is strongly reduced and consequently its linewidth is decreased dramatically. Benefiting from the narrow linewidth, large modulation depth, and giant magnetic field enhancement at the MP resonance, the cavity-coupled metamaterial sensor has very high sensitivity (S =400 nm/RIU, S* =26/RIU) and figure of merit (FOM =33, FOM* =4215), which suggests that the proposed metamaterials have potential in applications of plasmonic biosensors.
关键词： Optical sensing and sensors,Narrow linewidth,Magnetic field enhancement,Photonic microcavity,Metamaterials
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Optical Switching Cell Based On Metamaterials And Ferrite Films
摘要： A principally new switching cell with four inputs and four outputs based on metamaterial and optically transparent ferrite films for processing a large amount of information is proposed in this work. The cell uses the spatial diversity of the information beams under action of the control magnetic field. The principle of the cell's operation is described; calculations of the spatial deviation of the beam and the reflection coefficients of the structure are carried out.
关键词： control magnetic field,optical switching cell,ferrite films,metamaterials,spatial diversity
更新于2025-09-10 09:29:36
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Magnetic field-induced electronic phase transition in the Dirac semimetal state of black phosphorus under pressure
摘要： Different instabilities have been confirmed to exist in the three-dimensional (3D) electron gas when it is confined to the lowest Landau level in the extreme quantum limit. The recently discovered 3D topological semimetals offer a good platform to explore these phenomena due to the small sizes of their Fermi pockets, which means the quantum limit can be achieved at relatively low magnetic fields. In this work, we report the high-magnetic-field transport properties of the Dirac semimetal state in pressurized black phosphorus. Under applied hydrostatic pressure, the band structure of black phosphorus goes through an insulator-semimetal transition. In the high pressure topological semimetal phase, anomalous behaviors are observed on both magnetoresistance and Hall resistivity beyond the relatively low quantum limit field, which is demonstrated to indicate the emergence of an exotic electronic state hosting a density wave ordering. Our findings bring the first insight into the electronic interactions in black phosphorus under intense field.
关键词： High magnetic field,Electron phase transition,Quantum limit,Black phosphorus
更新于2025-09-10 09:29:36