Reflection and transmission of narrow beams at a dielectric interface is analysed. It is confirmed that for arbitrary incidence two types of beams - Elegant Hermite-Gaussians of linear polarization and Elegant Laguerre-Gaussians of circular polarization, both defined in the interface plane - can be treated as vector normal modes of the interface. Excitation of higher-order modes by cross-polarization coupling is described by changes of mode indices induced by generalised transmission and reflection matrices. It is explicitly shown that, off-axis in general, spectral placements of the excited optical vortices are determined by elements of these matrices, depended in turn on beam incidence. Numerical simulations of beam reflection entirely confirm theoretical predictions. The current paper is a continuation and extension of a previous work by W. Nasalski [Phys. Rev. E 74, 056613 (2006)].
The degenerate case of normal incidence and reflection of an optical beam (both paraxial and non-paraxial) at a plane isotropic dielectric interface, which is azimuthally symmetric in terms of the momentum-spatial variation of Fresnel coefficients but not in terms of the fundamental polarization inhomogeneity of the incident field, requires in-depth analyses. In this paper, we use the reflection and transmission coefficient matrix formalism to derive an exact field expression of a normal-reflected diverging beam. The availability of the exact field information allows controlled variations of t…
Recently a hypothesis explaining the non-resonant mechanism of subwavelength imaging granted by a dielectric microsphere has been suggested. In accordance to the hypothesis, the far-field image of a subwavelength scatterer strongly coupled to a microsphere by near fields is offered by the scatterer polarization normal to the sphere surface. The radiation of a closely located normally oriented dipole is shaped by the microsphere so that the transmitted wave beam has a practically flat phase front. Then this beam turns out to be imaging -- keeping the subwavelength information about the dipole l…
High-index spherical nanoparticles with low material losses support sharp high-Q electric and magnetic resonances and exhibit a number of interesting optical phenomena. Developments in fabrication techniques have enabled the further study of their properties and the investigation of related optical effects. After deposition on a substrate, the optical properties of a particle change dramatically due to mutual interaction. Here, we consider a silicon spherical nanoparticle on a dielectric one-layered substrate. At the normal incidence of light, the layer thickness controls the contribution of t…
Skolkovo Institute of Science and Technology（斯科尔科沃科学技术研究所）；Osipyan Institute of Solid State Physics RAS（奥西皮扬固体物理研究所）；PN Lebedev Physical Institute of RAS（列别捷夫物理研究所）
Replacement of ensemble averaging by the use of a broadband source in scattering of light from a one-dimensional randomly rough interface between two dielectric media
Elusive features in photonic and electronic devices can be detected by means of advanced, time-domain spectroscopic techniques. In this letter we introduce a novel kind of modulation spectroscopy, based on the optomechanical interaction of photonic and mechanical modes. Applying the technique to a Si metasurface and its drum-like mechanical modes, we detect narrow-band quasi-Bound-State-in-the-Continuum (q-BIC) modes close to normal incidence, where their measurement can be hindered by a high symmetry protection and undesired background modes. Showing a visibility enhancement of more than one …
Enhanced magneto-optical intensity effect in a helicity-preserving all-dielectric metasurface at Mie resonances and the anapole state
Russian Quantum Center（俄罗斯量子中心）；Moscow Institute of Physics and Technology (MIPT)（莫斯科物理技术学院）；Faculty of Physics, M.V. Lomonosov Moscow State University（莫斯科国立大学物理系）；National Engineering Research Center of Electromagnetic Radiation Control Materials, University of Electronic Science and Technology of China（电子科技大学电磁辐射控制材料国家工程研究中心）；State Key Laboratory of Electronic Thin-Films and Integrated Devices, University of Electronic Science and Technology of China（电子科技大学电子薄膜与集成器件国家重点实验室）
High index dielectric spherical particle supports the high-$Q$ resonant Mie modes that results in a regular series of sharp resonances in the radiation pressure. A presence of perfectly conducting metal surface transforms the Mie modes into the extremely high-$Q$ magnetic bonding or electric anti-bonding modes for close approaching of the sphere to the surface. We show that the electromagnetic plane wave with normal incidence results in repulsive or attractive resonant optical forces relative to metal for excitation of the electric bonding or magnetic anti-bonding resonant modes respectively. …
A dielectric laser accelerator, operating at optical frequencies and GHz pulse rate, is expected to produce attosec electron bunches with a moderate beam current at high energy. For relativistic electrons, the attosec bunch has a spatial length of a few nanometers, which is well suited for generating high-brightness superradiance in the VUV, EUV, and x-ray spectra. Our study shows that the brilliance of coherent undulator radiation driven by a short-bunch beam with 1~10 fC bunch charge from a dielectric laser accelerator is comparable to or higher than that of a synchrotron in the 0.1 ~ 3 keV …
Comparative Study of Optical and Magneto-Optical Properties of Normal, Disordered and Inverse Spinel Type Oxides
采用脉冲激光沉积法在高温和低温下制备了Co $_3$ O $_4$、ZnFe $_2$ O $_4$、CoFe $_2$ O $_4$、ZnCo $_2$ O $_4$和Fe $_3$ O $_4$薄膜，得到了具有光滑表面形貌的正、反以及无序的单相尖晶石氧化物薄膜。在0.5 ~ 8.5 eV的宽光谱范围内用椭圆偏振光谱法测定了介电函数，并与在1.7 T的磁场下用磁光克尔效应（MOKE）光谱法在1.7 ~ 5.5 eV的光谱范围内测定的介电张量的磁光响应进行了比较。晶场，价间和亚晶格间电荷转移跃迁，从O $_{2p}$过渡到金属阳离子3d或4s带被确定在主对角线元素和磁光活性非对角线元素的介电张量。取决于阳离子无序的程度，导致局部对称性畸变，磁光响应被认为是最强的高晶体质量的反尖晶石和无序的正常尖晶石结构，相反的第一原理研究的CoFe $_2$ O $_4$和ZnFe $_2$ O $_4$。研究结果为更深入地理解这种材料系统中的光-物质相互作用提供了基础，这种材料系统对与器件相关的现象和工程至关重要。
We study coupling of leaky Berreman modes in polar dielectric films (SiO2) through a thin metallic layer (gold) and show the familiar signatures of normal mode splitting. Due to very large negative real part of the dielectric function of gold, the splitting shows up only for extremely thin coupling layers. In contrast, coupling of Berreman modes through a dielectric spacer layer reveals novel possibilities of having bound states in continuum, albeit in the limit of vanishing losses. It is shown that the corresponding dispersion branches of the symmetric and antisymmetric modes can cross. BIC i…
