Search results for "Toe"
showing 10 items of 3824 documents
All-optical signal processing at ultra-low powers in bottle microresonators using the Kerr effect.
2010
We present experimental results on nonlinear, ultra-low power photonics applications based on a silica whispering-gallery-mode microresonator. Our bottle microresonator combines an ultrahigh quality factor of Q10(8) with a small mode volume V. The resulting Q(2)/V-ratio is among the highest realized for optical microresonators and allows us to observe bistable behavior at very low powers. We report single-wavelength all-optical switching via the Kerr effect at a record-low threshold of 50 microW. Moreover, an advantageous mode geometry enables the coupling of two tapered fiber waveguides to a bottle mode in an add-drop configuration. This allows us to route a CW optical signal between both …
Modelling resonant coupling between microring resonators addressed by optical evanescent waves
2004
In this paper we study the properties of microring resonator structures fabricated with high-index-of-refraction dielectric material. These structures concentrate light and can produce very strong optical potential gradients. They are of great interest for the trapping, manipulation and transport of cold atoms near surfaces. The study consists of two parts: in the first part we investigate the symmetry properties of the resonator response for simple models of the microring structures. In the second part we present detailed numerical calculations of the actual spectra for realistic microfabricated structures. We employ the direct space integral equation method (DSIEM). This method, based on …
WS 2 /MoS 2 Heterostructures through Thermal Treatment of MoS 2 Layers Electrostatically Functionalized with W 3 S 4 Molecular Clusters
2020
The preparation of 2D stacked layers combining flakes of different nature gives rise to countless numbers of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides, WS2 /MoS2 , has awakened great interest owing to its photovoltaic and photoelectrochemical properties. Solution as well as dry physical methods have been developed to optimize the synthesis of these heterostructures. Here, a suspension of negatively charged MoS2 flakes is mixed with a methanolic solution of a cationi…
Purcell factor for 3D- dipolar emitter coupling to 2D- plasmonic waveguides
2011
We theoretically investigate spontaneous emission of a quantum (3D) dipolar emitter located near a (2D) plasmonic waveguide of arbitrary form. The channels into which emitter couples (plasmon, scattering, electron-hole pairs creation) are well identified.
Conditions for waveguide decoupling in square-lattice photonic crystals
2004
We study coupling and decoupling of parallel waveguides in two-dimensional square-lattice photonic crystals. We show that the waveguide coupling is prohibited at some wavelengths when there is an odd number of rows between the waveguides. In contrast, decoupling does not take place when there is even number of rows between the waveguides. Decoupling can be used to avoid cross talk between adjacent waveguides.
Kerr Optical Frequency Combs With Multi-FSR Mode Spacing in Silica Microspheres
2021
We experimentally demonstrate Kerr optical frequency combs (OFCs) with mode spacing of 1, 2, 3, 5, 6, and 8 free spectral ranges (FSRs) corresponding to 0.4, 0.8, 1.2, 2, 2.4, and 3.2 THz, respectively, in silica microspheres pumped by CW C-band lasers in the anomalous dispersion range. Experimental realizations are based on using standard telecom equipment and components such as SMF-28e fiber for producing microspheres and fiber tapers for pump coupling and OFC outcoupling. Numerical simulation is performed to support the experimental results and explain the observed spectral asymmetry in OFCs by the influence of the 3rd-order dispersion.
An equivalent single-layer approach for free vibrations analysis of smart laminated thick composite plates
2012
An equivalent single-layer model for the free vibration analysis of smart laminated plates is presented. The electric and magnetic fields are assumed to be quasi-static and third-order in-plane kinematics is employed to adequately take the shear influence into account when the plate thickness increases. The model governing equations are the plate equations of motion written in terms of mechanical primary variables and effective stiffness coefficients, which take the multifield coupling effects into account. The model shows that the surfaces magneto-electric boundary conditions enter the definitions of the laminate forces and moments resultants. Moreover, it reveals that new stiffness terms,…
Purcell-enhancement of the radiative PL decay in perylenediimides by coupling with silver nanoparticles into waveguide modes
2017
In this work, an interesting approach to enhance the coupling between excitons and plasmons is proposed by integrating highly luminescent perylenediimides (PDIs) and Ag metal nanoparticles (MNPs) in the core of a multilayer dielectric waveguide. The combination of the weak plasmonic coupling and the high scattering of MNPs gives rise to a significant improvement of the PDI photoluminescence and Purcell factor (PF) in forward-scattering geometry. Furthermore, when the PDI-MNP system is used as the core of a multilayer waveguide, a Purcell factor enhancement larger than 10 is observed, which is explained by an increase in the exciton-plasmon coupling under the light confinement in the wavegui…
Aluminum Plasmonics: Fabrication and Characterization of Broadly Tunable Plasmonic Surfaces for Plasmon Molecule Strong-Coupling and Fluorescence Enh…
2018
Our work based on previous studies [1, 2] confirms, that simple aluminum nanostructures can be utilized as effective plasmonic resonators over a broad range of frequencies and wavelengths. The nanostructured surfaces, fabricated by electron-beam lithography demonstrated relatively narrow-band resonances and are suitable for various plasmonic applications ranging from metal enhanced fluorescence to strong-coupling [1, 2, 3, 4, 5] experiments. We represent data for molecule-plasmon coupling near the strong coupling limit and demonstrate that these aluminum structures do act as fluorescence increasing substrates. In this work, we used two different types of dyes. We studied the narrow band j-a…
Carotenoid bioaccessibility in pulp and fresh juice from carotenoid-rich sweet oranges and mandarins.
2015
Citrus fruits are a good source of carotenoids for the human diet; however, comparative studies of carotenoids in different citrus food matrices are scarce. In this work the concentration and bioaccessibility of carotenoids in sweet oranges and mandarins with marked differences in carotenoid composition were evaluated in pulp and compared to those in fresh juice. The pulp and juice of the red-fleshed Cara Cara sweet orange variety was highly rich in carotenes (mainly lycopene and phytoene) compared to standard Navel orange, while β-cryptoxanthin and phytoene predominated in mandarins. Total carotenoid content in the pulp of the ordinary Navel orange and in the red-fleshed Cara Cara orange, …