284 citations · 2.2k across the 91 of their papers we have counts for
95 papers
Exceptional Point Degeneracy as Desirable Operation Point of Oscillator Array with Discrete Nonlinear Gain and Radiating Elements
Alireza Nikzamir, Filippo Capolino
An oscillator array prefers to operate at an exceptional point of degeneracy (EPD) occurring in a waveguide periodically loaded with discrete nonlinear gain and radiating elements.…
The Azimuthally-Radially Polarized Beam: Helicity and Momentum Densities, Generation and Optimal Chiral Light
Albert Herrero-Parareda, Filippo Capolino
We investigate the optical properties of the azimuthally-radially polarized beam (ARPB), a superposition of an azimuthally polarized beam and a radially polarized beam, which can b…
Parametric Modeling of Serpentine Waveguide Traveling Wave Tubes
Kasra Rouhi, Robert Marosi, Tarek Mealy +2
A simple and fast model for numerically calculating small-signal gain in serpentine waveguide traveling-wave tubes (TWTs) is described. In the framework of the Pierce model, we con…
Time Modulation to Manage and Increase the Power Harvested From External Vibrations
Alireza Nikzamir, Kasra Rouhi, Alexander Figotin +1
We investigate how a single resonator with a time-modulated component extracts power from an external ambient source. However, the collected power is largely dependent on the preci…
Wide Band Interaction Impedance and Mode Excitation in Glide Symmetric Double Corrugated Waveguides for mm-wave TWTs
Nelson Castro, Miguel Saavedra-Melo, Eva Rajo-Iglesias +1
Focusing on traveling wave tube (TWT) applications, the interaction impedance between an electron beam and electromagnetic modes in three distinct, but related, corrugated waveguid…
Frozen Mode Regime in an Optical Waveguide With Distributed Bragg Reflector
Nathaniel Furman, Tarek Mealy, Md Shafiqul Islam +5
We introduce a glide symmetric optical waveguide exhibiting a stationary inflection point (SIP) in the Bloch wavenumber dispersion relation. An SIP is a third order exceptional poi…
Lasing at a Stationary Inflection Point
Albert Herrero-Parareda, Nathaniel Furman, Tarek Mealy +4
The concept of lasers based on the frozen mode regime in active periodic optical waveguides with a 3rd-order exceptional point of degeneracy (EPD) is advanced. The frozen mode regi…
Design of a Modified Coupled Resonators Optical Waveguide Supporting a Frozen Mode
Mohamed Y. Nada, Tarek Mealy, Md Shafiqul Islam +5
We design a three-way silicon optical waveguide with the Bloch dispersion relation supporting a stationary inflection point (SIP). The SIP is a third order exceptional point of deg…
Analytical Solution for Space-Charge Waves in a Two-Stream Cylindrical Electron Beam
Tarek Mealy, Robert Marosi, Kasra Rouhi +1
We present an analytical method to compute the wavenumbers and electric fields of the space-charge-wave eigenmodes supported by a two-stream electron beam, consisting of a solid in…
Pulse Generation Based on a Microstrip Circuit with Fourth Order Degenerate Band Edge
Dmitry Oshmarin, Alireza Nikzamir, Michael M. Green +1
A pulse generation scheme is proposed based on a structured resonance in a cavity where the non-conventional energy distribution is concentrated in its middle part. The cavity is f…
Highly Sensitive Coupled Oscillator Based on an Exceptional Point of Degeneracy and Nonlinearity
Alireza Nikzamir, Filippo Capolino
We propose a scheme for obtaining highly-sensitive oscillators in a coupled-resonator system with an exceptional point of degeneracy (EPD) and a small instability. The oscillator w…
Exceptional Points of Degeneracy with Indirect Bandgap Induced By Mixing Forward and Backward Propagating Waves
Tarek Mealy, Filippo Capolino
We demonstrate that exceptional points of degeneracy (EPDs) are obtained in two coupled waveguides without resorting to gain and loss. We show the general concept that modes result…
Reduced Plasma Frequency Calculation Based on Particle-In-Cell Simulations
Tarek Mealy, Robert Marosi, Filippo Capolino
We propose a scheme to calculate the reduced plasma frequency of a cylindrical-shaped electron beam flowing inside of a cylindrical tunnel, based on results obtained from Particle-…
Degenerate Distributed Feedback Photonic Structure with Double Grating Exhibiting Degenerate Band Edge
Tarek Mealy, Filippo Capolino
We propose a degenerate version of the Bragg condition, associated to a degenerate band edge (DBE). A standard Bragg condition can be implemented using a periodic grating that oper…
One-transmitter Multiple-receiver Wireless Power Transfer System Using an Exceptional Point of Degeneracy
Fatemeh Mohseni, Amin Hakimi, Alireza Nikzamir +2
Robust transfer efficiency against the various operating conditions in a wireless power transfer system remains a fundamentally important challenge. This challenge becomes even mor…
Three-Way Serpentine Slow-Wave Structures with Stationary Inflection Point and Enhanced Interaction Impedance
Robert Marosi, Tarek Mealy, Alexander Figotin +1
We introduce two novel variants of the serpentine waveguide slow-wave structure (SWS), often utilized in millimeter-wave traveling-wave tubes (TWTs), with an enhanced interaction i…
Wave-Controlled Metasurface-Based Reconfigurable Intelligent Surfaces
Ender Ayanoglu, Filippo Capolino, A. Lee Swindlehurst
Reconfigurable Intelligent Surfaces (RISs) are programmable metasurfaces that can adaptively steer received electromagnetic energy in desired directions by employing controllable p…
An Accurate Analytic Model for Traveling Wave Tube Dispersion Relation
Ahmed F. Abdelshafy, Filippo Capolino, Alexander Figotin
Abstract -- We construct an analytical model for the dispersion of the hot modes in a traveling wave tube (TWT) based on the Lagrangian field theory, upgrading its constants to be…
Frozen mode in an asymmetric serpentine optical waveguide
Albret Herrero Parareda, Ilya Vitebksiy, Jacob Scheuer +1
The existence of a frozen mode in a periodic serpentine waveguide with broken longitudinal symmetry is demonstrated numerically. The frozen mode is associated with a stationary inf…
Enhanced Sensitivity of Degenerate System Made of Two Unstable Resonators Coupled by Gyrator Operating at an Exceptional Point
Kasra Rouhi, Alireza Nikzamir, Alexander Figotin +1
We demonstrate that a circuit comprising two unstable LC resonators coupled via a gyrator supports an exceptional point of degeneracy (EPD) with purely real eigenfrequency. Each of…
Third Order Modal Exceptional Degeneracy in Waveguides with Glide-Time Symmetry
Farshad Yazdi, Tarek Mealy, Alireza Nikzamir +2
The dispersion of a three-way waveguide is engineered to exhibit exceptional modal characteristics. Two coupled waveguides with Parity-Time (PT) symmetry have been previously demon…
Triple Ladder Lumped Circuit with Sixth Order Modal Exceptional Degeneracy
Farshad Yazdi, Alireza Nikzamir, Tarek Mealy +2
We introduce a circuit topology based on a simple triple-ladder circuit realized with lumped reactive components that provides a sixth order degenerate band-edge (6DBE). The 6DBE i…
Experimental Demonstration of a New Oscillator Concept Based on Degenerate Band Edge in Microstrip Circuit
Dmitry Oshmarin, Ahmed F. Abdelshafy, Alireza Nikzamir +2
The first experimental demonstration of an oscillator based on a periodic, resonant microstrip circuit with a degenerate band edge (DBE) is presented. The DBE is a fourth-order exc…
Force Detection of Electromagnetic Beam Chirality at the Nanoscale
Abid Anjum Sifat, Filippo Capolino, Eric O. Potma
Many nanophotonic applications require precise control and characterization of electromagnetic field properties at the nanoscale. The chiral properties of the field are among its k…