Research on OAM propagation analysis with infinitesimal dipoles?5 answersResearch on OAM propagation analysis with infinitesimal dipoles has been extensively explored in recent studies. Various models, such as the infinitesimal dipole method customized for OAM EM fields, circular arrays of infinitesimal dipoles for OAM wave sources and receivers, and circular arrays of half-wavelength dipoles for OAM wave generation and reception, have been utilized. These studies have investigated the impact of different factors on OAM wave propagation, including the influence of the ground plane on OAM communication, the effects of conducting plates on OAM-based wireless communication, and the modeling of radiation patterns of aperiodic arrays using an infinitesimal dipole model. The findings contribute to optimizing OAM-based communication systems for realistic environments.
Do the log-normal distribution can be used as a image turbulence?5 answersThe log-normal distribution is commonly used to model turbulence in various contexts. It has been argued that a log-skew-normal (LSN) distribution may be more appropriate for turbulence generated by multiple changing sources. However, empirical evidence shows that the dissipation of kinetic energy in the global ocean follows a nearly log-normal distribution, even at large horizontal scales. Experimental studies on wind tunnel turbulence also support the log-normality of cascading processes. On the other hand, the log-normal distribution does not generally apply to the sum of independent random variables. Additionally, the log-stable distribution has been found to accurately describe the probability density function of velocity derivatives in a turbulent boundary layer. Therefore, while the log-normal distribution is commonly used in turbulence analysis, alternative distributions may be more appropriate in certain cases.
How the OAM-MIMO perform on free space optical communication with IM/DD?5 answersOAM-MIMO performs well in free space optical communication with intensity modulation and direct detection (IM/DD) systems. The use of OAM modes in MIMO coherent FSO communication systems can minimize the impact of atmospheric turbulence (AT) distortions and improve system performance. Additionally, the incorporation of OAM-MIMO with spatial mode multiplexing (SMM) and mode diversity schemes can enhance transmission capacity, mitigate multipath fading, and reduce atmospheric turbulence distortions. Furthermore, the use of OAM mode-group multiplexing (OAM-MGM) with transmitter mode diversity can increase system reliability under turbulence, reducing system interruption probability. The non-orthogonal OAM-MIMO system with fractional OAM modes also shows better performance compared to traditional MIMO systems, as it integrates more data streams into signals with larger power, resulting in lower bit error rates.
Download and unzip the GPhyLab01_PhaserJSIntroExample_210902.zip3 answersThe abstracts provided do not contain any information related to downloading and unzipping a specific file named "GPhyLab01_PhaserJSIntroExample_210902.zip."
How can incoherent light be used to generate OAM?5 answersIncoherent light can be used to generate orbital angular momentum (OAM) beams by miniaturizing spiral phase plates and integrating them with structural color filters. These optical elements act as building blocks that encode both color and OAM information in the form of colorful optical vortices. By achieving spatio-temporal coherence using only an incoherent white light source, pairs of transparent substrates that contain matching positions of these vortices can form a reciprocal optical lock and key system. Additionally, a photonic crystal-based OAM generator has been proposed, which allows for high-accuracy beam alignment and scalability of topological charges. Another approach involves using a standard silica optical fiber, where a properly tilted input laser beam is injected into the fiber cladding to break the axial symmetry and generate OAM beams. These methods have potential applications in various fields such as optical communication, super-resolution imaging, and high-dimensional quantum computing.
How can we design metasurfaces that generate wideband OAM vortex beams?3 answersMetasurfaces that generate wideband OAM vortex beams can be designed using various approaches. One approach is to use active metasurfaces in reflection manner, which can generate reconfigurable OAM vortex beams with high purity in a specific frequency range. Another approach is to design flat Pancharatnam-Berry (PB) metasurfaces with low RCS, which can generate scattered vortex waves with orbital angular momentum (OAM). Additionally, all-dielectric geometric metasurfaces can be used to generate perfect vortex beams (PVBs) with specific topological charges (TCs) based on tailored spiral phase distributions. Furthermore, an all-graphene geometric metasurface operating in the terahertz (THz) band can generate multidimensional vortices by introducing the superposition of two helical phases with the same topological charge within orthogonal circularly polarized (CP) channels. These design approaches provide different methods for generating wideband OAM vortex beams with various applications in optical communication and manipulation.