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Dispersion of electromagnetic waves in coaxial cylindrical rippled-wall waveguide including plasma layer
(2022-01-01)
Asadiamiri, F.
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Chaudhary, K.
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Ali, J.
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Bahadoran, M.
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Nejati, Malihe
Electronic technologies, especially in the microwave and terahertz frequency ranges, including plasma show better interaction efficiency and higher output power as compared to apparatus with the vacuum. Also, in these frequency ranges, the plasma-filled high-power waveguides can support TE and TM modes. Therefore, in this study, the dispersion relation of electromagnetic (EM) waves in a new rippled-wall waveguide structure contain the plasma layer and coaxial dielectric geometry is numerically studied. The Maxwell equations and boundary conditions are employed to investigate and analyze the dispersion relation in TM mode for coaxial geometry dielectric rippled-wall waveguide contain the plasma layer. High-frequency radiations are observed from the proposed configuration. It is found that the frequency of the wave increases with a decrease in the corrugation amplitude and period. Moreover, a decrease in frequency is observed with an increase in dielectric radius and a decrease in plasma radius.
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Dispersion characteristics of terahertz transverse electric mode in a smooth-wall cylindrical waveguide with a degenerate plasma layer
(2020-05-01)
Asadiamiri, F.
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Nejati, M.
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Chaudhary, K.
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Baboli, M.
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Ali, J.
The propagation of transverse electric mode in a cylindrical metallic smooth-wall waveguide contains a dielectric rod and a cold collisionless unmagnetized degenerate plasma layer is analytically investigated in the terahertz frequency region. The dispersion relations of fast and slow waves for this mode are derived and solved numerically. The effects of geometrical and physical parameters such as dielectric, plasma and metal radii, and dielectric permittivity on the dispersion characteristics of terahertz transverse electric mode and its frequency spectrum are studied. It is shown that the decrease of dielectric permittivity and metal radius, and the increase of degenerate plasma radius leads to higher frequency fast waves. It is also indicated that an increase in the dielectric radius results in a decrease in the frequency of fast waves. In addition, it is found that by reducing the dielectric rod radius and with increasing metal radius, the frequency is increased in the slow waves. Finally, it is shown that the increase in dielectric permittivity causes a decrease in the frequency of both fast and slow waves.
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Terahertz cherenkov radiation excited by an electron beam in a cylindrical metallic rippled-wall waveguide
(2020-04-01)
Asadiamiri, F.
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Ali, J.
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Bahadoran, M.
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Chaudhary, K.
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Yupapin, P. P.
The Cherenkov excitation of terahertz (THz) radiation by the interaction of an electron beam with the transverse magnetic modes of electromagnetic waves in a new configuration of cylindrical metallic rippled-wall waveguide (CMRWW) including an unmagnetized degenerate plasma layer and a dielectric rod is studied. In addition, the electric field profiles and the growth rates of these waves are investigated by deriving the wave equation and the dispersion relation for the proposed configuration. The effects of physical parameters such as dielectric and plasma radii, corrugation amplitude, and corrugation period on the dispersion relation, electric field profiles and growth rates of the terahertz radiation are discussed. It is shown that by choosing appropriate parameters of the electron beam and the waveguide, one can generate high power radiation in the terahertz range.
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Ultrafast all-optical ALU operation using a soliton control within the cascaded InGaAsP/InP microring circuits
(2019-02-04)
Soysouvanh, S.
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Phongsanam, P.
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Mitatha, S.
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Ali, J.
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Yupapin, P.
A dark-bright soliton conversion is used to perform the two arithmetic logic unit operations namely adder and subtractor operations. The advantage of the system such as power stability, non-dispersion and the dark-bright soliton phase conversion control can be obtained. The input source into the circuit is the bright soliton pulse, with the pulse width of 35 ps, the peak power at 1.55 µm is 1 mW. By using the dark-bright soliton conversion pair, the generated logic bits can be controlled, and the secure bits can be achieved. The simulation results show the output signal with a minimum loss of only 0.1% with respect to a low input power of 1 mW, and ultra-fast response time of about 1 ps can be achieved. It gives the ultra-high bandwidth of more than 40 Gbits<sup>−1</sup>. The circuit composes six microring resonators made of InGaAsP/InP material with smaller ring radii of 1.5 µm, and the total physical scale of the circuit less than 100 µm<sup>2</sup>.
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Ultra-fast electro-optic switching control using a soliton pulse within a modified add-drop multiplexer
(2018-09-01)
Soysouvanh, S.
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Jalil, M. A.
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Amiri, I. S.
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Ali, J.
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Singh, G.
We have proposed the use of a soliton pulse that propagates within a modified add-drop filter, which is made of a GaAsInP/P material. It is in the form of a Panda-ring resonator, from which a bright/dark soliton pulse is input into a system via an input port. The conversion between bright and dark soliton pulses is introduced at the 3 dB coupler, i.e. the change in phase of π/2. But it is not superimposed each other. The output solitons obtained at the through and drop ports are bight and dark solitons respectively. Both signals can be used to form “ON’ and “OFF” or “1” and “0”, which are useful for the digital bit generation. The switching speed of the system can be improved by employing the two nonlinear side rings. In application, secure output bits can be arranged by using the alternative input solitons or the control ports, where the input bright and dark solitons can be converted into output bits. This means that the output bits can be randomly switched between “1” and “0”, which can be identified by the sender. Moreover, the additional information can be multiplexed via the add port and transmitted in either free space or optical fiber via the whispering gallery mode and through port outputs. Finally, the electro-optic switching can be transferred and the electronic switching by the embedded stacked layers, where the ultrafast switching of light input can lead the ultrafast electrical switching speed. The switching speed of ~ 5 fs and the offset time of ~ 220 fs of the “on” and OFF” are achieved by using the selected ring parameters.
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Consciousness as a quantum dynamic effect
(2016-10-01)
Poznanski, R. R.
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Cacha, L. A.
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Ali, J.
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Aur, D.
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Perez Velazquez, J. L.
Electromagnetic quantum field interactions provide a deeper understanding of the emergence of consciousness through an ontological interpretation of quantum mechanics. Quasiparticle interactions in brain matter can produce "virtual" particles, hitherto mathematical conveniences, which reflect the manifold images of brain activities in terms of effects on charged particles that have physical quantum effect similar to the Aharonov-Bohm effect in quantum field theory. Electromagnetic potentials in the quantum domain pervade the entire brain through causative interactions. The exchange of energy quanta during quantum field interactions emerge as distinct patterns of quasiparticles and their entanglement produces waves of "virtual" particles with periodicities of discrete energies tethered through a common quantum potential as they interact and collectively represent the emergence of self-awareness as a quantum dynamic effect carried on the magnetic vector potential throughout the brain. This is caused by the magnetic dipole moments sensitivity to the phase shifts entrained by the zeitgeber acting on dipolar molecules in interfacial water. The emergence of consciousness is inseparable (spatiotemporally) in the sense that the endogenous electromagnetic field (and therefore the forces acting on the particles) vanish yet neurophenomenologically separate from the physical through the magnetic dipole moments sensitivity to the phase shifts of the coherent system. The subjective aspect of consciousness or phenomenal consciousness facilitates qualia as quantum information through information-physical interactions that metastabilize into rhythms unfolding through resonance into access consciousness as cognizable associable representations of subjective experiences. The transition from subjectivity occurs non-reductively from the microlevel to the macrolevel as a mechanism of spontaneous breaking of symmetry resulting from "photon" behavior of interfacial water instantiated by macroergic effects in the nuclei of neurons through a continuous supply of metabolic energy. The emergence of consciousness in living organisms disappears once autopoietic processes in populations of neurons cease to function.
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A comprehensive treatment of parametric effect in a silicon microring resonator
(2016-05-18)
Nawi, I. N.M.
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Ali, J.
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Yupapin, P. P.
Silicon microring resonator provides a new platform to form the building block for all-optical circuits, where it could be integrated on a single chip as a passive or active components. Here, we report a comprehensive treatment of parametric effect in a symmetrical add/drop silicon microring resonator with 5 μm radius operating within telecom wavelength spectrum or C-band ranging from 1530 nm to 1565 nm. The power outputs of the system are analyzed by using transfer matrix method. The FSR and FWHM have been optimized. The results demonstrated here will pave the way towards the new on-chip and chip-to-chip architecture and structure for low power and high bandwidth applications especially for all-optical switch and optical modulator.
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Soliton pulse induces TPA effect in a silicon MRR all-optical switch
(2016-05-18)
Nawi, I. N.M.
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Ali, J.
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Yupapin, P. P.
One of the critical problems in achieving a real practical all-optical switching devices is the requirement for a strong material nonlinearity. A strong material nonlinearity is crucial in order to achieve a low switching power. However, silicon-based all-optical switches require extremely high switching power due to its relatively weak nonlinear optical properties. To overcome this limitation, we have designed an all-optical switch configuration based on silicon microring resonator structure and demonstrated the switching operation based on the nonlinear effects induced by a soliton pulse. The soliton pulse induces free-carrier concentration through two-photon absorption (TPA) effect and this leads to enhance the refractive index change and enhance the nonlinearity of the silicon. Thus, the silicon microring resonator alters the nonlinear phase shift which is required for switching.
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Erratum: Laser-Induced Graphite Plasma Kinetic Spectroscopy under Different Ambient Pressures (Chinese Physics Letters (2015) 32:4 043201)
(2015-06-01)
Chaudhary, K.
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Rosalan, S.
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Aziz, M. S.
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Bahadoran, M.
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Ali, J.
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Laser-induced graphite plasma kinetic spectroscopy under different ambient pressures
(2015-04-01)
Chaudhary, K.
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Rosalan, S.
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Aziz, M. S.
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Bohadoran, M.
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Ali, J.
The laser induced plasma dynamics of graphite material are investigated by optical emission spectroscopy. Ablation and excitation of the graphite material is performed by using an 1064nm Nd:YAG laser in different ambient pressures. Characteristics of graphite spectra as line intensity variations and signal-to-noise ratio are presented with a main focus on the influence of the ambient pressure on the interaction of laser-induced graphite plasma with an ambient environment. Atomic emission lines are utilized to investigate the dynamical behavior of plasma, such as the excitation temperature and electron density, to describe emission differences under different ambient conditions. The excitation temperature and plasma electron density are the primary factors which contribute to the differences among the atomic carbon emission at different ambient pressures. Reactions between the plasma species and ambient gas, and the total molecular number are the main factors influencing molecular carbon emission. The influence of laser energy on the plasma interaction with environment is also investigated to demonstrate the dynamical behavior of carbon species so that it can be utilized to optimize plasma fluctuations.

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