Analysis of the Substrate Effect on the Zero-Backward Scattering Condition of a Cu2O Nanoparticle under Non-Normal Illumination

The presence of a substrate is one of the most important limitations of the real application of the directional conditions. These conditions allow the control of the spatial distribution of light scattering of nanoparticles. While the zero-forward condition is quite sensitive to any change of the surrounding medium, like the substrate, the zero-backward scattering seems to be less sensitive and very stable under normal illumination. In this letter, the zero-backward scattering condition was investigated on a homogenous Cu2O spherical subwavelength particle, both theoretically and experimentally. In particular, the influence of the substrate and the impinging direction on the angular distribution of light scattering under this directional condition were studied. We observed that the zero-backward scattering condition was also sensitive to the presence of a substrate beneath when a non-normal illumination was considered. We believe that our finding is quite interesting from a practical point of view and for the real implementation of directional scattering in various applications like cloaking, light-emitting devices, photovoltaic devices, bio-sensing, and many more.M.H. thanks the National Natural Science Foundation of China for financial support (Project Nos. 294 U1532112, 11375198, 11574280). B.G.-C. wants to thank the financial support from the Agencia Estatal de Investigación and FEDER for the Project TEC2016-77242-C3-1-R AEI/FEDER, UE and Comunidad de Madrid (SINFOTON-CM) grant number P2013/MIT-2790

An indirect method of imaging the Stokes parameters of a submicron particle with sub-diffraction scattering

In this work, we report an indirect way to image the Stokes parameters of a sample under test (SUT) with sub-diffraction scattering information. We apply our previously reported technique called parametric indirect microscopic imaging (PIMI) based on a fitting and filtration process to measure the Stokes parameters of a submicron particle. A comparison with a classical Stokes measurement is also shown. By modulating the incident field in a precise way, fitting and filtration process at each pixel of the detector in PIMI make us enable to resolve and sense the scattering information of SUT and map them in terms of the Stokes parameters. We believe that our finding can be very useful in fields like singular optics, optical nanoantenna, biomedicine and much more. The spatial signature of the Stokes parameters given by our method has been confirmed with finite difference time domain (FDTD) method.The authors wish to acknowledge the financial support National Key Research and Development Program of China (2017YFF0107100), National Natural Science Foundation of China (NSFC) (61501239), NSFC-2017 (International Young Scientist Research Fund no. 61750110520) and the “Zijin Professor Project” of Nanjing University of Science and Technology. MH thanks the National Natural Science Foundation of China for financial support (Project nos. U1532112, 11375198, 11574280). BGC thanks the funding through the R&D Program SINFOTON S2013/MIT-2790 of the Comunidad de Madrid and from Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) for the Project TEC2016-77242-C3-1-R AEI/FEDER, UE.Publicad

Electric and magnetic dipolar response of Germanium spheres: Interference effects, scattering anisotropy and optical forces

We address the scattering cross sections, and their consequences, for submicrometer Germanium spheres. It is shown that there is a wide window in the near infrared where light scattering by these particles is fully described by their induced electric and magnetic dipoles. In this way, we observe remarkable anisotropic scattering angular distributions, as well as zero forward or backward scattered intensities, which until recently was theoretically demonstrated only for hypothetically postulated magnetodielectric spheres. Also, interesting new effects of the optical forces exerted on these objects are now obtained.Comment: 13 pages, 4 figure

Imaging the scattering field of a single GaN nanowire

In this work, a single gallium nitride (GaN) nanowire has been examined by our previously reported technique parametric indirect microscopic imaging (PIMI). Mapping of the nanoscale scattering signals from GaN nanowire has been achieved with PIMI system. A comparison with classical far field microscopy and FDTD simulations is included to show the relevant differences and the strength of this technique. In PIMI, highly defined modulated illumination, far field variation quantification, and filtering process resolve the nanoscale scattering field distribution in the form of polarization parameters. We believe that our system provides us a platform to understand the physics of these nanoscale scattering fields from optical nanoantennas.The authors wish to acknowledge the financial support National Key Research and Development Program of China (2017YFF0107100), National Natural Science Foundation of China (NSFC) (61501239), NSFC-2017 (International Young Scientist Research Fund No. 61750110520) and the 'Zijin Professor Project' of Nanjing University of Science and Technology. B G C wants to thank the financial support from Agencia Estatal de Investigación and FEDER for the Project TEC2016-77242-C3-1-R AEI/FEDER, UE and Comunidad de Madrid for the SINFOTON-CM Research Program (S2013/MIT-2790).Publicad

Interaction of nanoparticles with substrates: effects on the dipolar behaviour of the particles

In this work, we present a numerical analysis of the surface electric field of a metallic nanoparticle (either 2D or 3D) interacting with a flat substrate underneath. The influence of the distance to the substrate, particle size, the surrounding media and the substrate optical properties is analyzed as a function of the incident wavelength. We show that these are crucial factors that change the field distribution associated to the dipolar behavior of the particle. A useful parameter for illustrating the changes in the angular distribution is θmax , the angle at which the maximum of the surface electric field is located

Efficient light management in a monolithic tandem perovskite /silicon solar cell by using a hybrid metasurface

Solar energy is now dealing with the challenge of overcoming the Shockley&-Queisser limit of single bandgap solar cells. Multilayer solar cells are a promising solution as the so-called third generation of solar cells. The combination of materials with different bandgap energies in multijunction cells enables power conversion efficiencies up to 30% at reasonable costs. However, interfaces between different layers are critical due to optical losses. In this work, we propose a hybrid metasurface in a monolithic perovskite-silicon solar cell. The design takes advantage of light management to optimize the absorption in the perovskite, as well as an efficient light guiding towards the silicon subcell. Furthermore, we have also included the effect of a textured back contact. The optimum proposal provides an enhancement of the matched short-circuit current density of a 20.5% respect to the used planar reference.This research was funded by Ministerio de Economía y Competitividad, grant number TEC2016-77242-C3-1-R Grant (AEI/FEDER, UE funds), and Comunidad de Madrid and FEDER program through the SINFOTON-CM Research (grant number S2013/MIT-2790) and SINFOTON2-CM (granT number S2018/NMT-4326) programs

Linear polarization degree for detecting magnetic properties of small particles

Motivated by the recent advances with magnetic nanoparticles, in this research we propose a new technique for their characterization based on the measurement of certain polarimetric parameters of the scattered light, such as the linear polarization degree when it is determined at a “right-angle” scattering configuration. We will show the sensitivity of its spectral evolution with the magnetic properties of the particle

Fiber Optic Temperature Sensor Based on Amplitude Modulation of Metallic and Semiconductor Nanoparticles in a Liquid Crystal Mixture

The response of an amplitude modulation temperature sensor based on a liquid crystal doped with either metallic or semiconductor nanoparticles has been theoretically analyzed. The effects of the concentration, the type of nanoparticle material, and liquid crystal compound have been studied in detail. The high sensitivity of light resonances to refraction index changes, in collaboration with the high thermooptic coefficients of liquid crystal materials, has resulted in the design of an optical fiber sensor with high temperature sensitivity. This sensitivity has been demonstrated to be dependent on nanoparticle concentration. A maximum theoretical sensitivity of 64 x 10(-2) dB/degrees C has been observed. Moreover, the sensitivity is highly linear with a regression coefficient of 99.99%.This work was supported in part by the Ministerio de Ciencia e Innovacion of Spain under Grant TEC2013-47342-C2-2-R and by the R&D Program SINFOTON S2013/MIT-2790 of the Comunidad de Madrid

Resolving multipolar scattering modes of submicron dielectric particle using parametric super resolution method

In this work, we show the spatial distribution of the scattered electromagnetic field of dielectric particles by using a new super-resolution method based on polarization modulation. Applying this technique, we were able to resolve the multipolar distribution of a Cu2O particle with a radius of 450 nm. In addition, FDTD and Mie simulations have been carried out to validate and confirm the experimental results. The results are helpful to understand the resonant modes of dielectric submicron particles which have a broad range of potential applications, such as all-optical devices or nanoantennas.The authors wish to acknowledge the financial support by National Key Research and Development Program of China (2017YFF0107100), National Natural Science Foundation of China (61501239), NSFC-2017 (International Young Scientist Research Fund no. 61750110520) and the “Zijin Professor Project” of Nanjing University of Science and Technology. MH thanks the National Natural Science Foundation of China for financial support (Project Nos. U1532112, 11375198, 11574280). BGC wants to thank the financial support from Agencia Estatal de Investigación and FEDER for the Project TEC2016-77242-C3-1-RAEI/FEDER, UE.Publicad

Design and experimental implementation of a multi-cloak paraxial optical system

Electromagnetic cloaking has being continuously pursued using a large variety of approaches. In recent years, this effect has been observed using either complex devices based on the so-called Transformation Optics or simple systems based on conventional optics with proper characteristics. In the latter case, a simple arrangement of lenses working in the paraxial regime can provide broadband visible cloaking in a wide area. In this work, we analyzed and generalized this method by proposing a five-lens system producing at least three potential invisible regions with a large cloaked area (>90% of the visual field). In particular, we developed the mathematical formalism and show, both numerically and experimentally, the successful operation of the cloaking system with the naked eye.AF-H wants also to express her grattitude to the Ministerio de Universidades for her predoctoral grant (FPU19/04133)