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- 摘要
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- 实验方案
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Handling Electromagnetic Radiation beyond Terahertz using Chromophores to Transition from Visible Light to Petahertz Technology
摘要： An increase of the operating frequencies of electromagnetic waves leads from the well-established terahertz technology to the visual and reaches petahertz radiation. It is shown that electromagnetic radiation close to petahertz is attractive for technology where knowledge about radio waves can be applied. The dimensions of such radiation are still classically macroscopic; however, molecular components such as resonators were used where quantum mechanics rules have to be considered. Constructions of coupled resonators for energy transfer are as well demonstrated as molecular components for optical metamaterials.
关键词： Dyes,FRET,Energy transfer,Reflectance,Petahertz,Visible light,Resonators,Metamaterials,Terahertz,Electromagnetic radiation
更新于2025-09-23 15:23:52
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A widely tunable bandpass filter adopting novel fully tunable resonators
摘要： A widely tunable bandpass filter adopting a novel fully tunable resonator is proposed in this letter. The fully tunable resonator is mainly consisted of an open ring, a frequency tuning structure, and a coupling tuning structure. Adopting the fully resonators, the center frequency, the input/output external Q value, and the coupling coefficients can be tuned at the same time. And the tuning range of a tunable filter adopting the novel fully tunable resonators can be expanded. The fully tunable resonators can be combined to achieve more excellent suppression performance. A widely tunable bandpass filter consisted of five fully tunable resonators with 86.5% frequency tuning range is designed, fabricated, and measured. The simulated results are in good agreement with the measured ones.
关键词： widely tunable filter,coupling tuning structure,open ring,fully tunable resonators,more excellent suppression
更新于2025-09-23 15:23:52
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Tunable Wide-Bandwidth Resonators Based on Layered Gallium Sulfide
摘要： Wide-bandwidth and high-frequency operation are the two desired properties from resonators in a wide range of applications, such as communication devices, energy harvesters, inertial sensors, and electronic components. However, achieving both of these prerequisites along with detectable vibration amplitudes is very challenging. Herein, nano-electromechanical resonators based on layered gallium sulfide (GaS) are demonstrated. These resonators show resonance frequencies in the range of 10–25 MHz under ambient conditions and a bandwidth of hundreds of kilohertz, which can be simply tuned by predetermining the dimensions of the devices. Therefore, this study emphasizes that, in addition to excellent performances in electronic and optoelectronic applications, GaS can also be implemented as a high performance core element in nanoresonator applications.
关键词： electromechanical properties,wide-bandwidth resonators,gallium sulfide,2D materials
更新于2025-09-23 15:23:52
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Vectorial perturbation theory for axisymmetric whispering gallery resonators
摘要： We propose a vectorial perturbation theory for axially symmetric, generally nonspherical whispering gallery resonators made of isotropic and anisotropic optical materials. It is based on analysis of the leading terms in the coupled equations for independent light-field components, as derived from Maxwell's equations, and true boundary conditions. Strong localization of the whispering gallery modes (WGMs) near the resonator rim, controlled by the azimuth modal number m, is the main prerequisite for our analysis. The theory gives high-precision expressions for the WGM frequencies and modal functions, including the evanescent effects. One of important applications of the theory is analysis of anticrossings of the WGM resonances in anisotropic resonators detected in experiments. Simple relations for the frequency avoidance gaps during the anticrossings are derived and compared with experimental data obtained in lithium-niobate-based WGM resonators. We show also that the vectorial effects substantially restrict the field of applicability of the scalar WGM models.
关键词： frequency avoidance gaps,whispering gallery resonators,anisotropic materials,vectorial perturbation theory,anticrossings
更新于2025-09-23 15:23:52
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Multi-channel silicon photonic receiver based on compact second-order microring resonators
摘要： A monolithically integrated multi-channel receiver fabricated on the Silicon-on-Insulator (SOI) platform is demonstrated experimentally. This receiver is composed of an eight-channel thermally tunable microring resonator (MRR) filter as the wavelength division multiplexing (WDM) demultiplexer and an array of high speed waveguide-integrated Ge-on-Si photodetectors (PDs) for light detection. Second-order MRRs were utilized in each channel to obtain steeper roll-off from passband to stopband and lower crosstalk. The receiver was fabricated by using CMOS-compatible fabrication process at IME A*STAR. With the thermal tunability, the channel spacing can be adjusted according to different channel grid. Lower than ?30 dB crosstalk and higher than 50 GHz 3-dB bandwidth was obtained for the demultiplexer with a channel spacing of 150 GHz. Proof-of-principle demonstration shows that each channel is capable of operating at a data rate of 10 Gb/s, resulting in an aggregate data rate of 80 Gb/s.
关键词： Silicon photonics,Wavelength division multiplexing,Optical receivers,Microring resonators,Optical interconnects
更新于2025-09-23 15:23:52
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Compensation of Distortions of Polarization Characteristics of Ring Resonators
摘要： The reasons of occurrence of polarization mode distortions and methods of their compensation are investigated. It is demonstrated that sensitivity of lasers with ring resonator to magnetic field may be reduced, if effect of induced polarization anisotropy to be compensated by means of installation of a mirror in resonator in certain position, which complies with the minimum ellipticity angle.
关键词： polarization characteristics of interference mirrors,ring optical resonators,phase anisotropy,information optics
更新于2025-09-23 15:23:52
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Realization of a three-dimensional photonic topological insulator
摘要： Confining photons in a finite volume is highly desirable in modern photonic devices, such as waveguides, lasers and cavities. Decades ago, this motivated the study and application of photonic crystals, which have a photonic bandgap that forbids light propagation in all directions1–3. Recently, inspired by the discoveries of topological insulators4,5, the confinement of photons with topological protection has been demonstrated in two-dimensional (2D) photonic structures known as photonic topological insulators6–8, with promising applications in topological lasers9,10 and robust optical delay lines11. However, a fully three-dimensional (3D) topological photonic bandgap has not been achieved. Here we experimentally demonstrate a 3D photonic topological insulator with an extremely wide (more than 25 per cent bandwidth) 3D topological bandgap. The composite material (metallic patterns on printed circuit boards) consists of split-ring resonators (classical electromagnetic artificial atoms) with strong magneto-electric coupling and behaves like a ‘weak’ topological insulator (that is, with an even number of surface Dirac cones), or a stack of 2D quantum spin Hall insulators. Using direct field measurements, we map out both the gapped bulk band structure and the Dirac-like dispersion of the photonic surface states, and demonstrate robust photonic propagation along a non-planar surface. Our work extends the family of 3D topological insulators from fermions to bosons and paves the way for applications in topological photonic cavities, circuits and lasers in 3D geometries.
关键词： 3D photonic topological insulator,split-ring resonators,Dirac surface states,robust photonic propagation,topological bandgap
更新于2025-09-23 15:23:52
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Anti-reflection high-index metasurfaces combining Mie and Fabry-Pérot resonances
摘要： Minimizing reflection losses is required for the efficient operation of a wide range of optical components. Anti-reflection coatings supporting Fabry-Pérot resonances are commonly used to solve this problem and can be applied on an industrial scale. Recent work has shown that reflections can also be reduced by placing an array of high-index nanostructures on a surface. In such coatings, anti-reflection is achieved by tailoring the scattering by optical Mie resonances. Here, we design and fabricate Si metasurfaces that combine both Fabry-Pérot and Mie resonances in a single metasurface to realize a multi-resonant broadband anti-reflection response. We optically characterize the metasurfaces demonstrating 4.1% AM1.5–averaged reflectance across the visible spectrum (425–900 nm). Our metasurface design strategy is generally applicable to different materials and frequency ranges, making our approach relevant for a broad variety of applications.
关键词： Mie resonators,Metasurface,Effective Medium,Anti-Reflection Coating (ARC),Fabry-Pérot resonances
更新于2025-09-23 15:23:52
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Enhancement of local electromagnetic fields by periodic optical resonators
摘要： The periodically profiled metasurfaces of silicon and of the same surfaces coated with a thin layer of silver are experimentally investigated to improve the signal-to-noise ratio in the observation of Raman light scattering from molecular compounds. The noise in this case is the unavoidable background molecular luminescence. Our experimental and computer simulation data demonstrate an anomalous optical response due to the excitation of metal-dielectric surface resonances. An enhanced Raman scattering signal is observed from 5,5'-dithiobis(2-nitrobenzoic) acid (DTNB) organic molecules deposited on the metasurface. The proposed metasurface provides a significant enhancement of the RS signal in comparison with the luminescence signal and is an efficient substrate for realising giant Raman scattering of light.
关键词： silicon,metasurface,dielectric resonators,nanostructures,plasmon resonance,giant Raman scattering of light
更新于2025-09-23 15:23:52
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Minimally asymmetric state conversion around exceptional singularities in a specialty optical microcavity
摘要： Exploiting scattering matrix (S-matrix) formalism, a unique route for manipulating the exceptional points (EPs) has been reported in a trilayer open optical microcavity with non-uniform real refractive index. The boundaries of the intermediate index layer are appropriately tapered. The cavity is partially pumped by transverse distribution of a balanced gain-loss profile. With strict restriction of balanced gain-loss, controlling infinitesimally small variation of gain-coefficient with simultaneous tapering parameter an EP has been encountered; which is being encircled in cavity parameter space to study dynamics of the coupled states around the EP in the context of robust selective flip-of-state phenomena with lower-asymmetry in state conversion efficiencies. Such a specialty trilayer microcavity with tunable width is reported for the first time; which turns out to be a specific approach to achieve maximum efficiency in conversion with minimum asymmetry. Considering suitable state-of-the-art techniques, this exclusive proposal may open up a fabrication feasible platform for device level implementation of system control exploiting EPs.
关键词： Microcavity devices,Mode-converters,Exceptional points,Avoided resonance crossing,Optical resonators
更新于2025-09-23 15:23:52