We propose and demonstrate dynamic formation of programmable waveguides on 2D coupled silicon ring resonator array with the size of 5×5. We successfully formed straight and bend waveguides with identical transmis...
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We study the interaction of emitters with a composite waveguide formed from two parallel optical nanofibers in regimes of experimental importance for atomic gases or solid-state emitters. Using the exact dyadic Green&...
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We study the interaction of emitters with a composite waveguide formed from two parallel optical nanofibers in regimes of experimental importance for atomic gases or solid-state emitters. Using the exact dyadic Green's function we comprehensively investigate the coupling efficiency and the fiber-induced Lamb shift accounting for variations in emitter positions and fiber configurations. This reveals coupling efficiencies and Purcell factors that are enhanced considerably beyond those using a single fiber waveguide, and robustness in the figures of merit. We finally investigate resonant dipole-dipole interactions and the generation of entanglement between two emitters mediated through the composite waveguide under excitation. We show that the concurrence can be enhanced for two fiber systems, such that entanglement may be present even in cases where it is zero for a single fiber. All-fiber systems are simple in construction and benefit from a wealth of existing telecommunications technologies, while enjoying strong couplings to emitters and offering interesting light-matter functionalities specific to slot waveguides.
This article aims to present a new method to reconstruct slowly varying width defects in 2D waveguides using locally resonant frequencies. At these frequen-cies, locally resonant modes propagate in the waveguide under...
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This article aims to present a new method to reconstruct slowly varying width defects in 2D waveguides using locally resonant frequencies. At these frequen-cies, locally resonant modes propagate in the waveguide under the form of Airy functions depending on a parameter called the locally resonant point. In this particular point, the local width of the waveguide is known and its location can be recovered from boundary measurements of the wavefield. Using the same process for different frequencies, we produce a good approximation of the width in all the waveguide. Given multi-frequency measurements taken at the surface of the waveguide, we provide a L-8-stable explicit method to reconstruct the width of the waveguide. We finally validate our method on numerical data, and we discuss its applications and limits.
We demonstrate a new waveguide geometry, namely a four-wire waveguide, which acts as a terahertz polarization-division multiplexer and a novel platform to realize versatile signal-processing functionalities into indep...
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We report on the fabrication and optical characterization of femtosecond (fs) laser written waveguides with varying geometries and parameters in a single crystal CVD grown diamond. Depressed circular cladding, halfrin...
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We report on the fabrication and optical characterization of femtosecond (fs) laser written waveguides with varying geometries and parameters in a single crystal CVD grown diamond. Depressed circular cladding, halfring, and double-line waveguides were fabricated. Design parameters such as core size and number of written tracks were varied to minimize propagation losses. Characterization of the waveguides was performed at 633 nm, which is close to the peak fluorescence wavelength of the nitrogen vacancy (NV) centers in diamond. Important experimental results revealing the dependence of the propagation loss and refractive index contrast on the design parameters were obtained. The maximum refractive index contrast was estimated as 22.7 x 10-5 for the fabricated waveguides. The measured propagation loss values of 2.05 dB/cm and 1.20 dB/cm, obtained with circular depressed cladding and half-ring waveguides, respectively, are, to the best of our knowledge, the lowest propagation loss values reported so far among fs laser written diamond waveguides.
Harnessing the properties of phonons on a chip, phononic integrated circuits are playing an increasingly important role in optoelectronic integration. To date, most of such phononic waveguides are realized by etching ...
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Harnessing the properties of phonons on a chip, phononic integrated circuits are playing an increasingly important role in optoelectronic integration. To date, most of such phononic waveguides are realized by etching a piezoelectric layer and forming a wire, which not only involves complicated fabrication processes but also limits integration with electronic and photonic elements on the same chip. To overcome these difficulties, here we propose and demonstrate a type of overlay slot phononic waveguide obtained by patterning a thin silicon cladding layer on an unetched gallium-nitride-on-sapphire substrate. We experimentally demonstrate the guiding and power splitting of gigahertz surface acoustic waves in such waveguides, with a measured propagation loss of about 1.80 dB/mm for the Rayleigh mode. We also theoretically predict that the Love mode in such waveguides can turn into a phononic bound state in the continuum under special conditions. Such waveguides introduce an alternative paradigm for phononic integrated circuitry and will enable applications in information processing, environmental monitoring, and noninvasive manipulation of biomolecules on a chip.
The effect of the presence of two probe waveguides on the dynamics of hyper-Raman processes is studied in terms of quantum Zeno and anti-Zeno effects. Specifically, the enhancement (diminution) of the evolution of the...
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The effect of the presence of two probe waveguides on the dynamics of hyper-Raman processes is studied in terms of quantum Zeno and anti-Zeno effects. Specifically, the enhancement (diminution) of the evolution of the hyper-Raman processes due to interaction with the probe waveguides via evanescent waves is viewed as quantum Zeno (anti-Zeno) effect. This study considers the two probe waveguides interacting with only one of the optical modes at a time. For instance, as a specific scenario, it is considered that the two non-degenerate pump modes interact with each probe waveguide linearly, while Stokes and anti-Stokes modes do not interact with the probes. Similarly, in another scenario, it is assumed both the probe waveguides interact with Stokes (anti-Stokes) mode simultaneously. The present results show that quantum Zeno (anti-Zeno) effect is associated with phase-matching (mismatching). However, it do not find any relation between the presence of the quantum Zeno effect and antibunching in the bosonic modes present in the hyper-Raman processes. Quantum Zeno (anti-Zeno) effects are investigated with the help of two probes interacting with a system undergoing the hyper-Raman process. Each probe mode interacts with one of the pump, Stokes, and anti-Stokes modes at a time. The results demonstrate that the quantum Zeno (anti-Zeno) effects are closely associated with the phase matching (mismatching). image
The aim of this work is to present theoretical tools to study wave propagation in elastic waveguides and perform multi-frequency scattering inversion to reconstruct small shape defects in elastic waveguides and plates...
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The aim of this work is to present theoretical tools to study wave propagation in elastic waveguides and perform multi-frequency scattering inversion to reconstruct small shape defects in elastic waveguides and plates. Given surface multi-frequency wavefield measurements, we use a Born approximation to reconstruct localized defect in the geometry of the plate. To justify this approximation, we introduce a rigorous framework to study the propagation of elastic wavefield generated by arbitrary sources. By studying the decreasing rate of the series of inhomogeneous Lamb mode, we prove the well-posedness of the PDE that model elastic wave propagation in two- and three-dimensional planar waveguides. We also characterize the critical frequencies for which the Lamb decomposition is not valid. By using these results, we generalize the shape reconstruction method already developed for acoustic waveguide to two-dimensional elastic waveguides and provide a stable reconstruction method based on a mode-by-mode spacial Fourier inversion given by the scattered field.
Emerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross-section, t...
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Emerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross-section, technological feasibility and structural perfection. All these criteria are met with self-assembled gallium phosphide (GaP) epitaxial nanowires. In this work, the effects of the nanowire geometry on their waveguiding properties are studied both experimentally and numerically. Cut-off wavelength dependence on the nanowire diameter is analyzed to demonstrate the pathways for fabrication of low-loss and subwavelength cross-section waveguides for visible and near-infrared (IR) ranges. Probing the waveguides with a supercontinuum laser unveils the filtering properties of the nanowires due to their resonant action. The nanowires exhibit perfect elasticity allowing fabrication of curved waveguides. It is demonstrated that for the nanowire diameters exceeding the cut-off value, the bending does not sufficiently reduce the field confinement promoting applicability of the approach for the development of nanoscale waveguides with a preassigned geometry. Optical X-coupler made of two GaP nanowires allowing for spectral separation of the signal is fabricated. The results of this work open new ways for the utilization of GaP nanowires as elements of advanced photonic logic circuits and nanoscale interferometers.
Continued development in the areas of communication, security, medicine, and safety is calling for terahertz-wave technologies to evolve beyond laboratory research and into the realm of real-world applications. Due to...
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Continued development in the areas of communication, security, medicine, and safety is calling for terahertz-wave technologies to evolve beyond laboratory research and into the realm of real-world applications. Due to the compatibility of waveguides with on-chip fabrication techniques and their ability to realize a small footprint, such structures provide a unique opportunity to achieve terahertz radiation generation in an on-chip arrangement, ideal for practical applications requiring terahertz electric fields. This review considers waveguiding arrangements that produce terahertz radiation using the nonlinear frequency-conversion techniques of optical rectification and difference frequency generation. The investigated terahertz radiation waveguiding sources are categorized into three different classes: those that confine and guide both the excitation electric fields and the generated terahertz radiation, those that confine and guide the excitation electric fields but not the generated terahertz radiation, and those that confine and guide the generated terahertz radiation but not the excitation electric fields. Various types of waveguides are surveyed from each category, including dielectric waveguides, metallic waveguides, photonic crystal waveguides, poled waveguides, and multiple waveguides embedded within one another. This review provides a detailed overview of state-of-the-art terahertz radiation waveguide sources, with the intent of aiding in the continuing development of such sources.
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