We present here a method for solving the electromagnetic wave-matter interaction, on the one hand in closed waveguides, single or multi-port, and on the other hand with infinite materials periodic in two directions. I...
详细信息
We present here a method for solving the electromagnetic wave-matter interaction, on the one hand in closed waveguides, single or multi-port, and on the other hand with infinite materials periodic in two directions. In this presentation, the guides are coaxial or rectangular, but extension to any regular guide section is straightforward. This paper presents a method for solving Maxwell's equations in real or virtual waveguides, using a decomposition of the DtN operator, and also introduces an adapted basis of the solution space based on a variational formulation. Finally, 2D axisymmetric and 3D finite elements are used. The text presents a number of resolutions of guided plane-wave scattering problems in a material, confirming the validity of the method and its generality.
We present a new methodology for measuring the gain and the linewidth enhancement factor of a semiconductor ridge-waveguide laser structure. The holographic methodology is based on a modified Mach-Zehnder interferomet...
详细信息
We present a new methodology for measuring the gain and the linewidth enhancement factor of a semiconductor ridge-waveguide laser structure. The holographic methodology is based on a modified Mach-Zehnder interferometer. Compared with existing methods, the holographic setup allows to measure intensity and phase related properties such as optical gain and linewidth enhancement factor spectrally and spatially resolved. The obtained values agree well with data acquired from standard gain measurements.
In this paper, we develop and analyze a new, to the best of our knowledge, semivectorial bidirectional operator marching method with fourth-order accuracy (Bi-OMM4) for three-dimensional optical waveguides. The fourth...
详细信息
In this paper, we develop and analyze a new, to the best of our knowledge, semivectorial bidirectional operator marching method with fourth-order accuracy (Bi-OMM4) for three-dimensional optical waveguides. The fourth-order semivector exponential scheme reproduces the exact reformulations for equations with pairs of bidirectional reflection operators based on the Dirichlet-to-Neumann (DtN) mapping. Implementations for large range step sizes in both directions are presented, and exact bidirectional range marching formulas are derived for each range-independent segment. The study compares the results obtained from the Bi-OMM4 with the fourthorder bidirectional beam propagation method based on the finite difference scheme (FD-Bi-BPM4) and the bidirectional operator marching method with second-order accuracy (Bi-OMM2) to validate the accuracy and effectiveness of Bi-OMM4 by analyzing several examples of uniform and longitudinally varying waveguides. The results show that the Bi-OMM4 is numerically faster than the FD-Bi-BPM4 by almost seven times for different transverse grid sampling points, and it offers higher accuracy than Bi-OMM2 without a significant increase in computation resources. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
Frequency shift detection is crucial for advancing quantum, laser and metrology technologies. Here, we propose a compact design for detecting frequency shift in GaAs waveguides with mode-coupled Bragg gratings, which ...
详细信息
Frequency shift detection is crucial for advancing quantum, laser and metrology technologies. Here, we propose a compact design for detecting frequency shift in GaAs waveguides with mode-coupled Bragg gratings, which provides enhanced sensitivity. Our proposed architecture features a main ridge waveguide with a Bragg grating, flanked by two curved ridge waveguides. This configuration exhibits an optical phenomenon characterized by a transmission crossing at the wavelength of the Bragg grating. Using particle swarm optimization and employing efficient figures of merit, we achieve a high transmission crossing. The observed asymmetric transmission crossing not only holds the promise for a compact on-chip laser frequency stabilizer, but also fosters the development of novel sensing platforms with heightened sensitivity. (c) 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
Three-dimensional (3D) microstructures were written by femtosecond (fs) laser aiming to manufacture waveguides inside niobium germanate glasses. The laser-induced damage threshold using 1030 nm fs-laser irradiation wa...
详细信息
Three-dimensional (3D) microstructures were written by femtosecond (fs) laser aiming to manufacture waveguides inside niobium germanate glasses. The laser-induced damage threshold using 1030 nm fs-laser irradiation was investigated, and the waveguides were written in different fluences. The morphology, structural information and refractive index changes of microstructures were discussed. The waveguide cross-section microscopy data shows an elliptical shape with a diameter varying with the applied pulse energy. The micro-Raman maps demonstrate the occurrence of structural modifications with different microregions along the laser propagation direction. The refractive index profiles point to the formation of at least one microregion containing a positive refractive index change along the laser propagation. Guided light transmission measurements demonstrate the formation of single-mode waveguides inscribed at low pulse energy (up to 132 nJ) and an emitting waveguide in the rare-earth-doped sample. The visible luminescent response of erbium ions in the waveguide output was demonstrated and supports the possibility of using these core waveguides for future 3D multi-functional photonic devices operating in the visible region.
Through the use of strain and induced piezoelectric fields, surface acoustic waves (SAWs) have been shown to control quantum information processes, such as single photon emission and the coherent transport of electron...
详细信息
Through the use of strain and induced piezoelectric fields, surface acoustic waves (SAWs) have been shown to control quantum information processes, such as single photon emission and the coherent transport of electron spins. Regarding the latter, systems using plane surface waves have provided suitable demonstration systems, but to build complexity, more control over the acoustic wave may be required. One method for acoustic control is the use of phononic crystals consisting of periodic arrays of nanofabricated holes on the surface of a device. These inclusions form a metamaterial-like layer with properties different from the host material to dictate the physics of wave motion. Exploiting these surface properties can lead to acoustic waveguides, which can be designed to control the path of the SAWs. The design parameters of a new type of phononic crystal waveguide are explored that use twofold elliptical cylinder inclusions to create a slow region that also limits coupling and radiative loss to bulk acoustic modes. Such a waveguide will be the foundational piece in an acoustic circuit that can then mediate complex spin transport geometries.
We demonstrate a versatile THz waveguide platform for tailored THz-induced orientation and alignment of gas molecules. The underlying waveguide structure is dispersionless, with a refractive index close to one, and en...
详细信息
We demonstrate a versatile THz waveguide platform for tailored THz-induced orientation and alignment of gas molecules. The underlying waveguide structure is dispersionless, with a refractive index close to one, and enhances the electric as well as the magnetic field up to a factor of five. These properties increase the detected transient birefringence signal by more than an order of magnitude compared to conventional THz free space focusing. We apply this new platform to align two molecular systems and compare the results to theory. Furthermore, we present THz pulse shaping for coherently controlled alignment.
Multilayer transparent ceramic planar waveguides were fabricated using a newly developed particle-loaded ink spraying method, characterized, and lased. waveguides with five Yb:YAG gain regions and four Lu:YAG index-ma...
详细信息
Multilayer transparent ceramic planar waveguides were fabricated using a newly developed particle-loaded ink spraying method, characterized, and lased. waveguides with five Yb:YAG gain regions and four Lu:YAG index-matched regions were produced for application as a "ribbon laser," as well as a homogeneous Yb:YAG waveguide. Elemental mapping revealed that the waveguide thicknesses varied from 40 to 69 mu m, comprised of layers of less than 10 mu m. The Yb concentration profiles were fit to a diffusion profile. The homogeneous and multilayer waveguides were tested in a laser cavity and produced similar slope efficiencies, with a maximum of 31% achieved. Their beam profiles provided evidence of the ribbon structure affecting the preferred mode. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.
In this letter, the cutoff frequencies of multilayered fully anisotropic circular waveguides with metallic walls are calculated in the general case, in which the waveguide's anisotropic material is magnetized by a...
详细信息
In this letter, the cutoff frequencies of multilayered fully anisotropic circular waveguides with metallic walls are calculated in the general case, in which the waveguide's anisotropic material is magnetized by an external magnetic bias which is obliquely oriented with respect to the waveguide's axis. This is a generalization of cases where the bias is aligned to the waveguide's axis and the material features gyrotropic behavior. This problem is solvable via a coupled-field volume integral equation-cylindrical Dini series expansion (CFVIE-CDSE) method, previously used for the calculation of electromagnetic (EM) scattering by anisotropic cylinders with oblique magnetic bias, by combining formerly constructed modified tensorial Green's functions (GFs) to account for the boundary conditions (BCs) on the metallic walls. We validate the extended CFVIE-CDSE method with the HFSS commercial software and we study a microwave application of a G-610 aluminum garnet ferrite-loaded waveguide, magnetized under oblique magnetic bias, where we compute the complex cutoff frequencies.
Line-waves are one-dimensional modes propagating at the interface between two planar complementary surfaces, characterized by tight transversal confinement of the field. Despite their unique guiding properties, their ...
详细信息
Line-waves are one-dimensional modes propagating at the interface between two planar complementary surfaces, characterized by tight transversal confinement of the field. Despite their unique guiding properties, their use in real microwave devices is still in the early stages, lacking a comprehensive design procedure and comparative analysis with conventional guiding structures. To fill this gap, here we report a simple and straightforward workflow for designing waveguides supporting 1D modes propagation. The design is based on the analytical relations existing between the surface impedance of the propagating modes and the sheet impedance of the metasurfaces, which allow quick retrieval of the geometrical parameters of the complementary metasurfaces sustaining the line-wave propagation. This approach is used to design several waveguiding layouts and compare their transmission performance through full-wave simulations accounting for dielectric and ohmic losses. Finally, experimental results for some selected designs in the microwave regime are provided, and a thoughtful comparison between a line-wave waveguide and an equivalent microstrip transmission line is carried out to assess the suitability of these devices for efficient high-frequency waveguiding.
暂无评论