Laserbasierte Herstellung metallischer und dielektrischer Nanopartikel zur Kontrolle von Licht auf der Nanoskala

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Experimental demonstration of surface plasmon polaritons reflection and transmission effects

Special integrated photonic surface structures composed of a dielectric semicircle ridge and a dielectric block placed on a metal substrate are proposed for the investigation of surface plasmon polariton (SPP) reflection and transmission effects. A fabrication method called microscope projection photolithography was employed for the preparation of the structures. Leakage radiation microscopy was applied for the excitation and observation of surface plasmon polaritons (SPPs). It was observed that SPPs exhibit a remarkable decrease in intensity when impinging onto the rectangular dielectric block. Nevertheless, the transmitted wave out of the dielectric block was always observable. The propagation behavior of both the reflected waves at two boundaries (air/dielectric and dielectric/air) and the transmitted wave inside the dielectric block were demonstrated for different SPP incident conditions. The variation of the angles of reflection and transmission with respect to the incident angle was analytically and experimentally investigated. An agreement between the calculated results and the experimental results was obtained. Our findings might allow for novel applications in sensing and analytics once the structures will be functionalized

UV-LED projection photolithography for high-resolution functional photonic components

The advancement of micro- and nanostructuring techniques in optics is driven by the demand for continuous miniaturization and the high geometrical accuracy of photonic devices and integrated systems. Here, UV-LED projection photolithography is demonstrated as a simple and low-cost approach for rapid generation of two-dimensional optical micro- and nanostructures with high resolution and accuracy using standard optics only. The developed system enables the projection of structure patterns onto a substrate with 1000-fold demagnification. Photonic devices, e.g., waveguides and microring resonators, on rigid or flexible substrates with varied geometrical complexity and overall structure dimensions from the nanometer to centimeter scale were successfully prepared. In particular, high-resolution gratings with feature sizes down to 150 nm and periods as small as 400 nm were realized for the first time by this approach. Waveguides made of doped laser active materials were fabricated, and their spontaneous emission was detected. The demonstrated superior performance of the developed approach may find wide applications in photonics, plasmonics, and optical materials science, among others

Point contact openings in surface passivated macroporous silicon layers

In this paper we demonstrate the preparation of point contact openings in surface passivated macroporous silicon layers. In our experiments we control the etching parameters to vary the percentage of these non-passivated local openings from 0% to 1.6%. We investigate the impact of these local openings in the passivating layer on the effective carrier lifetime. These local openings reduce the measured effective carrier lifetime with increasing percentage of the non-passivated areas. We measure effective carrier lifetimes up to 10 ?s on 29 ?m-thick fully passivated macroporous silicon samples. We develop and apply a 3-dimensional numerical model to calculate carrier lifetimes as a function of pore morphology, surface recombination, percentage of non-passivated area, and bulk lifetime. The model agrees with the experimental measurements. We find a surface recombination velocity of (S pass=22.8 -1.4 1.6) cm s -1 for the passivated surfaces and S np=(2200 -1400 1500) cm s -1 for the non-passivated surface. � 2012 Elsevier B.V

Electromagnetic resonances of silicon nanoparticle dimers in the visible

We report the optical response of dielectric sub-micrometer particle dimers with resonances in the visible, illustrating a hybridization of electric and magnetic dipolar modes of their individual constituents. The experimental results, corroborated by the numerical calculations, reveal the contributions to the scattering from homogeneous pairs of dipolar electric-electric and magnetic-magnetic modes, as well as from the heterogeneous electric-magnetic modes, induced due to the overlap between the electric and magnetic polarizabilities of single scatterers. The silicon nanoparticles are fabricated on glass by a laser printing method and characterized by polarization-resolved dark-field microscopy. Extensive numerical calculations are carried out to investigate the influence of the morphology and oxidation of the dimers on the optical response in order to properly model their hybridization.The authors acknowledge financial support of this work from Deutsche Forschungsgemeinschaft (DFG) (SFB/TRR 123 “PlanOS”). M.K.S. and J.A. acknowledge funding from the project FIS2013-41184-P of the Spanish Ministry of Economy and Competitiveness, the ETORTEK IE14-393 NANOGUNE’14 project of the Department of Industry of the Government of the Basque Country, project IT756-13 of the Department of Education and Culture of the Basque Country, and scholarship AP-2012-4204 from the Spanish Ministry of Education, Culture and Sport. A.B.E. and B.N.C. acknowledge support from the Ministry of Education and Science of Russian Federation (project 14.B25.31.0019).Peer Reviewe

Laser-ablative engineering of phase singularities in plasmonic metamaterial arrays for biosensing applications

International audienceBy using methods of laser-induced transfer combined with nanoparticle lithography, we design and fabricate large-area gold nanoparticle-based metamaterial arrays exhibiting extreme Heaviside-like phase jumps in reflected light due to a strong diffractive coupling of localized plasmons. When employed in sensing schemes, these phase singularities provide the sensitivity of 5 x 10(4) deg. of phase shift per refractive index unit change that is comparable with best values reported for plasmonic biosensors. The implementation of sensor platforms on the basis of such metamaterial arrays promises a drastic improvement of sensitivity and cost efficiency of plasmonic biosensing devices. (C) 2014 AIP Publishing LLC

Demonstration of optical vortex propagation in on-chip rectangular dielectric waveguides

Orbital angular momentum (OAM) of light provides an additional degree of freedom for multiplexing the data streams in optical communications, increasing further the channel capacity [1]. Applications of OAM for both classical data transmission [2] and quantum information [3] have been demonstrated. The key step towards robust, suitable for massive production, and cost-efficient OAM-assisted communications is the development of compact, on-chip integrable optical components. Summary form only given. Orbital angular momentum (OAM) of light provides an additional degree of freedom for multiplexing the data streams in optical communications, increasing further the channel capacity [1]. Applications of OAM for both classical data transmission [2] and quantum information [3] have been demonstrated. The key step towards robust, suitable for massive production, and cost-efficient OAM-assisted communications is the development of compact, on-chip integrable optical components.In this work we demonstrate propagation of vortex modes, carrying OAM, in rectangular dielectric waveguides, which can be produced with standard photolithography process. We show by numerical simulation that the specific superposition of waveguide eigenmodes form the quasi-degenerate modes carrying light with high purity states of OAM. Fig. 1(a-f) shows the amplitude and phase distributions of the dominant field component of quasi-TE vortex modes with topological charges ℓ = 1, 2 and 3, propagating in the few-mode waveguide with 10μmκ10μm PMMA core (n1 = 1.4794) and pure silica substrate (n2 = 1.444, n3 = 1). Numerical modelling has been performed using Matlab with full vector finite difference modesolver [4] for waveguide eigenmodes determination. We also demonstrate experimentally the propagation of the 1st order OAM mode in a polymer rectangular waveguide (4.5 μm × 4.1 μm core made of Ormosil with n1 = 1.50 at 1550 nm is deposited on silica substrate)

Optical vortex propagation in few-mode rectangular polymer waveguides

We demonstrate that rectangular few-mode dielectric waveguides, fabricated with standard lithographic technique, can support on-chip propagation of optical vortices. We show that specific superpositions of waveguide eigenmodes form quasi-degenerate modes carrying light with high purity states of orbital angular momentum

Nanocrystalline resonant silicon nanoparticle for highly efficient second harmonic generation

Silicon is a centrosymmetric material, and the studies of nonlinear optical properties of silicon nanoparticles are primarily targeting the third-harmonic generation effects. Here we demonstrate that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique exhibit strong second-harmonic generation (SHG) effects. We attribute an unexpectedly high yield of the nonlinear conversion to a nanocrystalline structure of nanoparticles supporting the Mie resonances. Our finding may open novel prospects for a design of nonlinear subwavelength light sources with exceptional functionalities fully integrated in Si-based nanoscale photonic circuits

Efficient Second-Harmonic Generation in Nanocrystalline Silicon Nanoparticles

Recent trends to employ high-index dielectric particles in nanophotonics are motivated by their reduced dissipative losses and large resonant enhancement of nonlinear effects at the nanoscale. Because silicon is a centrosymmetric material, the studies of nonlinear optical properties of silicon nanoparticles have been targeting primarily the third-harmonic generation effects. Here we demonstrate, both experimentally and theoretically, that resonantly excited nanocrystalline silicon nanoparticles fabricated by an optimized laser printing technique can exhibit strong second-harmonic generation (SHG) effects. We attribute an unexpectedly high yield of the nonlinear conversion to a nanocrystalline structure of nanoparticles supporting the Mie resonances. The demonstrated efficient SHG at green light from a single silicon nanoparticle is 2 orders of magnitude higher than that from unstructured silicon films. This efficiency is significantly higher than that of many plasmonic nanostructures and small silicon nanoparticles in the visible range, and it can be useful for a design of nonlinear nanoantennas and silicon-based integrated light source