The paper describes results of the numerical simulation and experimental characterization of plasmonic gratings and waveguides in the optical range of 1520-1630 nm. Gold structures were coated with a 630-nm thick tetr...
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The paper describes results of the numerical simulation and experimental characterization of plasmonic gratings and waveguides in the optical range of 1520-1630 nm. Gold structures were coated with a 630-nm thick tetraethylorthosilicate layer to achieve higher coupling efficiency for plasmonic gratings using lensed optical probes. We experimentally demonstrated gold input/output plasmonic gratings with an efficiency of about -3.8 +/- 0.2 dB per grating. The measured loss of the plasmonic mode propagating over the surface of the gold waveguide was 0.14 +/- 0.02dB/mu m. The work was carried out with the aim of studying integrated plasmonic structures for the development of a hybrid photonic-plasmonic integrated technology
We describe a leaky-wave antenna based on a parallel-plate metal waveguide, suitable for use in the terahertz range. The emission from the antenna is highly directional. It can be controlled by shaping the waveguide p...
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ISBN:
(纸本)9781479982721
We describe a leaky-wave antenna based on a parallel-plate metal waveguide, suitable for use in the terahertz range. The emission from the antenna is highly directional. It can be controlled by shaping the waveguide plates, for engineering of terahertz wave fronts.
We demonstrate a compact and broadband polarization independent 3-dB coupler for the O-band on silicon-on-insulator platform. Using the multi-parameter adiabaticity engineering protocol, unwanted coupling between eige...
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We demonstrate a compact and broadband polarization independent 3-dB coupler for the O-band on silicon-on-insulator platform. Using the multi-parameter adiabaticity engineering protocol, unwanted coupling between eigenmodes in mode evolution couplers are redistributed for dual polarization modes and multiple wavelengths, resulting in a large operating bandwidth for both TE and TM polarizations. The fabricated device has a bandwidth of 70 nm with a compact mode evolution region of 27 mu m.
A novel and highly effective method for scalable production of Augmented Reality (AR) waveguides can be achieved through the integration of inkjet printing with large-area Nanoimprint Lithography (NIL). In this work, ...
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ISBN:
(纸本)9781510686069;9781510686076
A novel and highly effective method for scalable production of Augmented Reality (AR) waveguides can be achieved through the integration of inkjet printing with large-area Nanoimprint Lithography (NIL). In this work, we show that the combination process of inkjet printing and large-area NIL are key to precisely create the intricate features necessary for high- performance AR waveguides at the required high degree of accuracy. Inkjet printing allows for precise deposition of materials, which is crucial for compensating for relief volumes and enabling the fabrication of modulated waveguide designs. Additionally, the large-area NIL complements the inkjet printing process by providing accurate replication of these designs over large surfaces with high throughput. This means that even as the size of the surface area increases, the quality and accuracy of the waveguide replication remain consistent. This aspect of the methodology is essential for achieving uniformity and reliability in the production process, particularly when working with surfaces beyond the traditional wafer scale. Here, we have used high refractive index (HRI) inkjet resin (n = 1.8) and an AR waveguide with blazed and binary gratings to demonstrate this methodology while imprinting multiple waveguides in one imprint cycle.
We study the transverse normal linear propagating modes within a cylindrical wave guide filled with a blue-phase liquid crystal, which is subjected to the cladding by means of soft anchoring boundary conditions. The a...
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We study the transverse normal linear propagating modes within a cylindrical wave guide filled with a blue-phase liquid crystal, which is subjected to the cladding by means of soft anchoring boundary conditions. The axis of the two dimensional helical structure of the blue phase is taken parallel to the cylindrical wave guide axis. We establish the coupled governing equations consisting of the electromagnetic Maxwell's equations in the presence of a blue phase and the equilibrium equations for the blue-phase texture resulting from the minimisation of both, the bulk and surface free energy. By assuming a low intensity electromagnetic field, we decouple the texture equation and solve it to obtain blue-phase configurations;parameterised for different anchoring energies from which calculate the band structure and electromagnetic fields associated to these textures. We find that the number of propagating modes in the blue-phase cored waveguide depends on the anchoring strength.
Spin and orbital angular momenta of light have been a subject of fundamental interest since long ago, classically associated with circular polarization and wave vector. In recent years, extraordinary spin angular mome...
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Spin and orbital angular momenta of light have been a subject of fundamental interest since long ago, classically associated with circular polarization and wave vector. In recent years, extraordinary spin angular momenta in structured electromagnetic waves have been investigated, mostly in subwavelength evanescent fields at the nanoscale. Here we present an in-depth theoretical analysis of the transverse spin density and related momentum induced by mode confinement inside waveguides, with alternating spin layers governed by guided mode spatial symmetry, different from and indeed richer than that in the evanescent region outside. Furthermore, hybrid guided modes with intrinsic helicity exhibit in addition longitudinal spin density. Such fundamental features are manifested through fascinating phenomenology relevant to spin-orbit coupling in nanophotonic waveguides. Thus, guided light intrinsically carrying a wealth of spin momenta holds promise of superb devices to control spin-orbit interaction within confined geometries throughout the electromagnetic spectra.
We address the problem of acoustic propagation in waveguides in presence of a uniform flow and with, locally, a spatially varying impedance boundary condition on the walls. In time harmonic regime, the Myers impedance...
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ISBN:
(纸本)9788888942483
We address the problem of acoustic propagation in waveguides in presence of a uniform flow and with, locally, a spatially varying impedance boundary condition on the walls. In time harmonic regime, the Myers impedance boundary condition is chosen. Classically, that is, in waveguides with rigid boundaries, multimodal formulations involve the expansion of the solution on the "rigid" transverse modes satisfying the Neumann boundary condition. Since these modes define a complete basis, the decomposition is still valid in segments with Myers boundary condition at the walls. However, because the boundary condition is not satisfied by the transverse modes, the series has poor convergence. This results in the appearance of Gibbs oscillations close to the treated wall. Our aim is to develop an improved multimodal methods, to remedy the problem of the low convergence of the series in the standard modal approach. In the case of waveguides with varying cross- section or of straight guides with impedance condition but without flow, it has been shown that this situation can be remedied by adding to the usual expansion an additional term (called supplementary mode). In this approach, the role of the supplementary mode is to restore asymptotically the right boundary condition. In the no flow case, the convergence of the scattering properties is increased from N- 1 in the standard modal method to N-5 in the formulation with a supplementary mode. The case of the limit toward a discontinuous impedance boundary conditions is also considered, leading to the constraint of an edge condition for the pressure at the discontinuities.
For a good THz waveguide, both low propagating loss and small mode width are usually very important. However, the high ohmic loss of metals and the high absorption loss of dielectric materials result in that it still ...
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ISBN:
(纸本)9781628418972
For a good THz waveguide, both low propagating loss and small mode width are usually very important. However, the high ohmic loss of metals and the high absorption loss of dielectric materials result in that it still remains a challenge to obtain the two capabilities at the same time. In this paper, planar dielectric-gap-metal (DGM) waveguides are presented to guide THz wave. According to the dispersion equations of the waveguides, we calculate their mode characteristics by numerical calculation, and we find that THz wave can propagate in the waveguides with low loss and simultaneously subwavelength mode width. When compared with the parallel-plate waveguide, the mode losses of the DGM waveguide can be 1-3 orders of magnitude lower, but the mode widths do not increase. The combination of low propagating loss and subwavelength mode width makes the DGM waveguides particularly useful for many THz applications such as sensing, communication, and imaging.
We experimentally demonstrate sinusoidal anti-coupling silicon-on-insulator strip waveguides, separated by 200 nm, that have a minimum inter-waveguide crosstalk suppression of 26.8 dB within the C-band for the fundame...
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ISBN:
(纸本)9781557529688
We experimentally demonstrate sinusoidal anti-coupling silicon-on-insulator strip waveguides, separated by 200 nm, that have a minimum inter-waveguide crosstalk suppression of 26.8 dB within the C-band for the fundamental transverse electric mode. (C) 2014 Optical Society of America
A compact polarization beam splitter (PBS) for silicon-based slot waveguides is proposed based on a multimode interference coupler, where an asymmetrical multimode waveguide (AMW), cut by a right angle at one corner, ...
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ISBN:
(纸本)9781628414479
A compact polarization beam splitter (PBS) for silicon-based slot waveguides is proposed based on a multimode interference coupler, where an asymmetrical multimode waveguide (AMW), cut by a right angle at one corner, is employed to efficiently separate the TE and TM modes. With the unique modal properties of the slot waveguides and corresponding optimized designs, the input '1E mode can almost pass through the AMW and then enter into the bar port, while a mirror image is formed at the cross port for the input TM mode due to the self-imaging effect. Meanwhile, tapered waveguide structures and S-bend are incorporated into the designed PBS for further enhancing the performance. According to the numerical results, a PBS with an AMW of 2.3 jam in length is achieved, where the extinction ratios are 16.6 and 20.9 dB, respectively, for '1E and TM modes, and the insertion losses are 1.37 and 0.81 dB, respectively, at the wavelength of 1.55 jam. For keeping extinction ratios over 15 and 20 dB for TE and TM modes, the bandwidths are around 59 and 73 nm, respectively, both covering the entire C-band. In addition, field evolution along the propagation distance through the PBS is also demonstrated.
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