المؤلفون: Kryzhanovskaya, N. V.¹ (AUTHOR) Nataliakryzh@gmail.com, Ivanov, K. A.¹ (AUTHOR), Fominykh, N. A.¹ (AUTHOR), Komarov, S. D.¹ (AUTHOR), Makhov, I. S.¹ (AUTHOR), Moiseev, E. I.¹ (AUTHOR), Guseva, J. A.² (AUTHOR), Kulagina, M. M.² (AUTHOR), Mintairov, S. A.² (AUTHOR), Kalyuzhnyy, N. A.² (AUTHOR), Lihachev, A. I.² (AUTHOR), Khabibullin, R. A.³ (AUTHOR), Galiev, R. R.³ (AUTHOR), Pavlov, A. Yu.³ (AUTHOR), Tomosh, K. N.³ (AUTHOR), Maximov, M. V.⁴ (AUTHOR), Zhukov, A. E.¹ (AUTHOR)

المصدر: Journal of Applied Physics. 9/14/2023, Vol. 134 Issue 10, p1-10. 10p.

مصطلحات موضوعية: *PLANAR waveguides, *QUANTUM dots, *LASERS, *COUPLING schemes, *INDIUM gallium arsenide, *RESONATORS

مستخلص: We report on InGaAs/GaAs quantum dot injection microdisk lasers laterally connected with a bus waveguide fabricated by planar technology from the same epi-structure. Various coupling schemes of microlaser with waveguide are studied including a microlaser attached to a waveguide (zero gap), a 100 nm gap for evanescence light outcoupling, and with a waveguide surrounding the resonator. The modes outcoupling and microlaser's loss (Q-factor) are analyzed by simulation of the lasers. A strong decrease in the number of the microdisk resonance lines associated with an increase in loss in the resonator due to the coupling with waveguide is observed in modeling and experimentally. We study the spectral and lasing parameters of the microdisk lasers, as well as characteristics of the outcoupled emission, and demonstrate efficient light outcoupling for 30 and 40 μm diameter continuous wave operating microdisk laser up to 96 °C. [ABSTRACT FROM AUTHOR]

المؤلفون: NICLAS, ANGÉLE¹ angele.niclas@math.cnrs.fr, SEPPECHER, LAURENT² laurent.seppecher@ec-lyon.fr

المصدر: SIAM Journal on Applied Mathematics. 2024, Vol. 84 Issue 1, p75-96. 22p.

مصطلحات موضوعية: *HELMHOLTZ equation, *PLANAR waveguides, *INVERSE problems, *WAVEGUIDES

مستخلص: This article presents a new method to reconstruct slowly varying width defects in two-dimensional waveguides using one-side section measurements at locally resonant frequencies. At these frequencies, locally resonant modes propagate in the waveguide up to a "cut-off"" position. In this particular point, the local width of the waveguide can be recovered. Given multifrequency data measured on a section of the waveguide, we perform an efficient layer stripping approach to recover, section by section, the shape variations. It provides an L infinity-stable method to reconstruct the width of a slowly monotonous varying waveguide. We validate this method on numerical data and discuss its limits. [ABSTRACT FROM AUTHOR]

المؤلفون: Cherouana, Abdelbaki¹ (AUTHOR) acherouana@cdta.dz, Benaissa, Salim¹ (AUTHOR), Bencheikh, Abdelhalim² (AUTHOR), Bouchama, Idris^3,4 (AUTHOR)

المصدر: Optical & Quantum Electronics. Nov2023, Vol. 55 Issue 12, p1-21. 21p.

مصطلحات موضوعية: *OPTICAL sensors, *PLANAR waveguides, *REFRACTIVE index, *TEMPERATURE

مستخلص: This study focuses on investigating how changes in temperature affect the sensitivities of an optical sensor that uses a SiO2:TiO2 planar waveguide, with particular emphasis on the fundamental modes sensitivities. The results showed that, by accurately determining the appropriate core thickness for each set of physical parameters of the waveguide, we not only increased the sensitivity, but also extended its stabilization range with respect to the temperature. The best results, in terms of values and stabilities of the sensitivities were obtained for a high refractive index of the core and selecting a measurand refractive index closest to that of substrate. As regards the geometrical parameters, the most favorable results can be attained for the core thicknesses located between the thickness corresponding to the maximum sensitivity at room temperature and the cut-off thickness of the TM0 mode, the sensitivity remain relatively stable at the vicinity of 0.41. However, for the monomode structure, the best results can be achieved for the core thicknesses situated between the thickness corresponding to the maximum sensitivity at room temperature and twice the cut-off thickness of the TE0 single mode, the average sensitivity is relatively constant at around 0.35. [ABSTRACT FROM AUTHOR]

المؤلفون: Dorin, Patrick¹ (AUTHOR), Khan, Mustafa¹ (AUTHOR), Wang, K. W.¹ (AUTHOR) kwwang@umich.edu

المصدر: Advanced Science. 10/26/2023, Vol. 10 Issue 30, p1-11. 11p.

مصطلحات موضوعية: *METAMATERIALS, *PLANAR waveguides, *EVIDENCE gaps, *ELASTIC waves, *WAVEGUIDES, *RESONANCE

مستخلص: Topological mechanical metamaterials unlock confined and robust elastic wave control. Recent breakthroughs have precipitated the development of 3D topological metamaterials, which facilitate extraordinary wave manipulation along 2D planar and layer‐dependent waveguides. The 3D topological metamaterials studied thus far are constrained to function in single‐frequency bandwidths that are typically in a high‐frequency regime, and a comprehensive experimental investigation remains elusive. In this paper, these research gaps are addressed and the state of the art is advanced through the synthesis and experimental realization of a 3D topological metamaterial that exploits multimodal local resonance to enable low‐frequency elastic wave control over multiple distinct frequency bands. The proposed metamaterial is geometrically configured to create multimodal local resonators whose frequency characteristics govern the emergence of four unique low‐frequency topological states. Numerical simulations uncover how these topological states can be employed to achieve polarization‐, frequency‐, and layer‐dependent wave manipulation in 3D structures. An experimental study results in the attainment of complete wave fields that illustrate 2D topological waveguides and multi‐polarized wave control in a physical testbed. The outcomes from this work provide insight that will aid future research on 3D topological mechanical metamaterials and reveal the applicability of the proposed metamaterial for wave control applications. [ABSTRACT FROM AUTHOR]

المؤلفون: Yu, X, Weeber, J-C, Markey, L, Arocas, J, Bouhelier, A, Leray, A, Colas des Francs, G

المصدر: Nanotechnology; 6/24/2024, Vol. 35 Issue 26, p1-9, 9p

مصطلحات موضوعية: WAVEGUIDE antennas, ANTENNAS (Electronics), PLANAR antennas, RADIO frequency, PLANAR waveguides, QUANTUM optics, QUANTUM dots

مستخلص: Integrated quantum photonic circuits require the efficient coupling of photon sources to photonic waveguides. Hybrid plasmonic/photonic platforms are a promising approach, taking advantage of both plasmon modal confinement for efficient coupling to a nearby emitter and photonic circuitry for optical data transfer and processing. In this work, we established directional quantum dot (QD) emission coupling to a planar TiO2 waveguide assisted by a Yagi-Uda antenna. Antenna on waveguide is first designed by scaling radio frequency dimensions to nano-optics, taking into account the hybrid plasmonic/photonic platform. Design is then optimized by full numerical simulations. We fabricate the antenna on a TiO2 planar waveguide and deposit a few QDs close to the Yagi-Uda antenna. The optical characterization shows clear directional coupling originating from antenna effect. We estimate the coupling efficiency and directivity of the light emitted into the waveguide. [ABSTRACT FROM AUTHOR]

: Copyright of Nanotechnology is the property of IOP Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Yelkenci, Tanju

المصدر: Frequenz; Jun2024, Vol. 78 Issue 5/6, p207-212, 6p

مصطلحات موضوعية: GEOPHYSICAL prospecting, DIELECTRIC waveguides, MOMENTS method (Statistics), ELECTROMAGNETIC waves, PLANAR waveguides, ELECTROMAGNETIC wave scattering

مستخلص: While reverse time migration (RTM) algorithm is commonly used in geophysical explorations, this paper addresses the RTM imaging procedure for reconstructing of lossy dielectric discontinuities in a planar waveguide using electromagnetic waves at a single frequency. The direct problem of the related configuration is solved via method of moments (MoM) to produce the synthetic scattered data to be used in RTM. The achievements of the method are examined and verified by including different numerical examples. It is shown that the RTM approach can be used as an alternative imaging methodology in parallel plate waveguide problems. [ABSTRACT FROM AUTHOR]

: Copyright of Frequenz is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Reyes-Romero, Arturo, Adrian Reyes, J.

المصدر: Waves in Random & Complex Media; Jun2024, Vol. 34 Issue 3, p1702-1725, 24p

مصطلحات موضوعية: ELECTROMAGNETIC wave propagation, CHOLESTERIC liquid crystals, MAXWELL equations, CONSTRUCTION slabs, STOCHASTIC analysis, PLANAR waveguides, FILLER materials

مستخلص: A stochastic theoretical analysis of electromagnetic wave propagation inside a planar slab waveguide filled with a cholesteric material, whose azimuthal angular component on its director n is randomly fluctuating is presented in this article. By means of van Kampen systematic expansion method, Maxwell's electromagnetic equations with random dielectric tensor and appropriate boundary conditions are obtained. As numerical examples, the effects of the randomness on the propagating constant, on the ratio between magnetic and electric modes, on the field profiles, and on the energy flow are presented and discussed. The results in this paper are consistent with those corresponding to the deterministic conventional waveguide. [ABSTRACT FROM AUTHOR]

: Copyright of Waves in Random & Complex Media is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Xing, Chang, Zhou, Bo, Yan, Dongpeng, Fang, Wei‐Hai

المصدر: Advanced Science; May2024, Vol. 11 Issue 17, p1-8, 8p

مصطلحات موضوعية: HETEROJUNCTIONS, OPTICAL waveguides, INFORMATION technology security, PLANAR waveguides, HALIDES, ENGINEERING, WAVEGUIDES, PHOSPHORESCENCE

مستخلص: Ensuring information security has emerged as a paramount concern in contemporary human society. Substantial advancements in this regard can be achieved by leveraging photonic signals as the primary information carriers, utilizing photonic logical gates capable of wavelength tunability across various time and spatial domains. However, the challenge remains in the rational design of materials possessing space‐time‐color multiple‐resolution capabilities. In this work, a facile approach is proposed for crafting metal‐organic halides (MOHs) that offer space‐time‐color resolution. These MOHs integrate time‐resolved room temperature phosphorescence and color‐resolved excitation wavelength dependencies with both space‐resolved ex situ optical waveguides and in situ heterojunctions. Capitalizing on these multifaceted properties, MOHs‐based two‐dimensional (2D) optical waveguides and heterojunctions exhibit the ability to tune full‐color emissions across the spectra from blue to red, operating within different spatial and temporal scales. Therefore, this work introduces an effective methodology for engineering space‐time‐color resolved MOH microstructures, holding significant promise for the development of high‐density photonic logical devices. [ABSTRACT FROM AUTHOR]

: Copyright of Advanced Science is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Kolenda, M., Kezys, D., Grinys, T., Vaitkevičus, A., Kadys, A., Reklaitis, I., Vaičaitis, V., Petruškevičius, R., Tomašiūnas, R.

المصدر: Optical & Quantum Electronics; May2024, Vol. 56 Issue 5, p1-16, 16p

مصطلحات موضوعية: GALLIUM nitride, CHEMICAL vapor deposition, FEMTOSECOND pulses, LASER pumping, PLANAR waveguides, WAVEGUIDES

مستخلص: We demonstrate a broadband second-harmonic generator for the green spectral range based on a periodical polarity GaN waveguide structure. We grew the structure with a periodicity of 4 μ m using an MOCVD (metal-organic chemical vapor deposition) reactor. We tested the structure using femtosecond laser pulse pumping and obtained the second harmonic ( λ SH =512 nm) conversion efficiency 0.79 · 10 - 7 % · W - 1 for the pump peak power of 440 kW inside the waveguide. Based on the theoretical modeling of the dispersion curves of the pump and the second harmonic, we found multiple crossings, including an extended crossing. We relate this fact to the experimentally measured broadened second harmonic spectrum. [ABSTRACT FROM AUTHOR]

: Copyright of Optical & Quantum Electronics is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Nadeem, Iram¹, Verri, Valentina², Martini, Enrica¹, Morgia, Fabio², Toccafondi, Alberto¹, Mattivi, Maurizio², Maci, Stefano¹ macis@ing.unisi.it

المصدر: IEEE Transactions on Antennas & Propagation. Nov2022, Vol. 70 Issue 11, p10632-10640. 9p.

مصطلحات موضوعية: BACKSCATTERING, PLANAR waveguides, ELECTRIC lines, INSERTION loss (Telecommunication), METAMATERIALS, EXPERIMENTAL design

مستخلص: This article presents the design and experimental characterization of microwave structures based on parity time-reversal duality symmetric bifilar edge waveguides (PTD-BEWs) realized through a parallel plate waveguide (PPW) loaded by a metasurface. The analyzed structures include transmission lines with bends and multiple line arrangements. Due to their unique symmetry properties, these structures are robust against backscattering, thus resembling the behavior of topological WGs, despite the fact they are reciprocal. This makes it possible to guide the electromagnetic (EM) waves along the edge with low insertion losses and unique matching properties. Measurements, performed in the frequency range between 24 and 32 GHz, have confirmed the feasibility of the theoretical concept. [ABSTRACT FROM AUTHOR]

: Copyright of IEEE Transactions on Antennas & Propagation is the property of IEEE and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)