scholarly journals General theory and observation of Cherenkov radiation induced by multimode solitons

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
M. A. Eftekhar ◽  
H. Lopez-Aviles ◽  
F. W. Wise ◽  
R. Amezcua-Correa ◽  
D. N. Christodoulides
Keyword(s):  
Optical Fibers ◽  
High Power ◽  
Cherenkov Radiation ◽  
Many Body ◽  
Multimode Fibers ◽  
Formidable Challenge ◽  
Theoretical Predictions ◽  
Radiation Induced ◽  
Soliton Fission ◽  
Physical Phenomena

AbstractAdvancements in computational capabilities along with the possibility of accessing high power levels have stimulated a reconsideration of multimode fibers. Multimode fibers are nowadays intensely pursued in terms of addressing longstanding issues related to information bandwidth and implementing new classes of high-power laser sources. In addition, the multifaceted nature of this platform, arising from the complexity associated with hundreds and thousands of interacting modes, has provided a fertile ground for observing novel physical effects. However, this same complexity has introduced a formidable challenge in understanding these newly emerging physical phenomena. Here, we provide a comprehensive theory capable of explaining the distinct Cherenkov radiation lines produced during multimode soliton fission events taking place in nonlinear multimode optical fibers. Our analysis reveals that this broadband dispersive wave emission is a direct byproduct of the nonlinear merging of the constituent modes comprising the resulting multimode soliton entities, and is possible in both the normal and anomalous dispersive regions. These theoretical predictions are experimentally and numerically corroborated in both parabolic and step-index multimode silica waveguides. Effects arising from different soliton modal compositions can also be accounted for, using this model. At a more fundamental level, our results are expected to further facilitate our understanding of the underlying physics associated with these complex “many-body” nonlinear processes.

Recent Developments in Rare-Earths Doped Nano-Engineered Glass Based Optical Fibers for High Power Fiber Lasers

2016 ◽  
Vol 75 (4) ◽  
pp. 195-208 ◽  
Author(s):  
Mukul C. Paul ◽  
S. Bysakh ◽  
Shyamal Das ◽  
Anirban Dhar ◽  
M. Pal ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Rare Earths ◽  
High Power ◽  
Fiber Lasers ◽  
Recent Developments

scholarly journals Review of the high-power vacuum tube microwave sources based on Cherenkov radiation

2020 ◽  
Author(s):  
Weiye Xu
Keyword(s):  
Output Power ◽  
High Power ◽  
Traveling Wave ◽  
Cherenkov Radiation ◽  
Continuous Wave ◽  
Vacuum Tube ◽  
Microwave Source ◽  
Vacuum Tubes ◽  
Traveling Wave Tubes ◽  
Microwave Sources

Since the first vacuum tube (X-ray tube) was invented by Wilhelm Röntgen in Germany, after more than one hundred years of development, the average power density of the vacuum tube microwave source has reached the order of 108 [MW][GHz]2. In the high-power microwave field, the vacuum devices are still the mainstream microwave sources for applications such as scientific instruments, communications, radars, magnetic confinement fusion heating, microwave weapons, etc. The principles of microwave generation by vacuum tube microwave sources include Cherenkov or Smith-Purcell radiation, transition radiation, and Bremsstrahlung. In this paper, the vacuum tube microwave sources based on Cherenkov radiation were reviewed. Among them, the multi-wave Cherenkov generators can produce 15 GW output power in X-band. Cherenkov radiation vacuum tubes that can achieve continuous-wave operation include Traveling Wave Tubes and Magnetrons, with output power up to 1MW. Cherenkov radiation vacuum tubes that can generate frequencies of the order of 100 GHz and above include Traveling Wave Tubes, Backward Wave Oscillators, Magnetrons, Surface Wave Oscillators, Orotrons, etc.

scholarly journals PHOTONIC CRYSTAL FIBRES DESIGN USING A MULTICRITERIA BASED SOFTWARE

2011 ◽  
Author(s):  
I. Sassi ◽  
N. Belacel ◽  
Y. Bouslimani ◽  
H. Hamam
Keyword(s):  
Photonic Crystal ◽  
Optical Fibers ◽  
Communication Systems ◽  
Inductive Learning ◽  
Single Mode ◽  
Crystal Fiber ◽  
Optical Propagation ◽  
Multicriteria Method ◽  
Crystal Fibers ◽  
Physical Phenomena

The single-mode optical fiber used currently in communication systems starts showing many limitations especially for the high rates. Several physical phenomena related to the optical propagation are the cause of these limitations. The use of photonic crystal fibers (PCF) makes it possible to control most of these phenomena. In this paper, a multicriteria method is used for the design of the photonic crystal fiber with the user-defined optical proprieties. This method combines the deductive and the inductive learning and it is introduced for the first time in the field of optical fibers. This multicriteria method proves to be a powerful tool for the PCF fibers design.

scholarly journals The Effect of Ionising Radiation on the Luminescence Properties of Fluoroperovskites

2021 ◽  
Author(s):  
◽  
Joseph Schuyt
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Ionising Radiation ◽  
Luminescence Properties ◽  
Readout System ◽  
Tissue Equivalent ◽  
Potential Applications ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena

<p>The luminescence of crystalline compounds can be used to monitor many physical phenomena, including doses of ionising radiation. Optically stimulated luminescence (OSL), thermoluminescence (TL), and radiophotoluminescence (RPL) have been successfully employed in dosimetry. However, few materials possess both the structural and luminescence properties required for medical dosimetry. This thesis aimed to investigate the luminescence features of the class of compounds known as fluoroperovskites. Emphasis was placed on studying the effects of irradiation on the luminescence properties, such that the compounds could be evaluated regarding potential applications in clinical dosimetry. Samples were primarily characterised using photoluminescence (PL), radioluminescence (RL), OSL, RPL, TL, and transmittance spectroscopy.  OSL was observed in the majority of samples due to the existence of electron trapping F-type centres. F-centre/Mn complexes were observed in all AMgF3:Mn compounds after irradiation and the energy levels of the complexes in each compound were experimentally determined. The most promising potential dosimeter host material was the near tissue-equivalent NaMgF3. When doped with Mn2+, the compound exhibited RPL via the formation of F-centre/Mn complexes and OSL via several trapping centres. The RPL could be probed independently to the OSL such that the compound could function as a hybrid OSL/RPL dosimeter. In the NaMgF3:Ln compounds, RPL occurred via the radiation-induced reduction Ln3+ → Ln2+ for Ln = Sm, Dy, and Yb. The reduction Sm3+ → Sm2+ was highly stable and could be non-destructively probed independently to the OSL. The Sm doped compound also exhibited radiation-induced conductivity that could be coupled with the RL, such that the compound could function as a real-time hybrid optical/electrical dosimeter. Charge kinetics, thermal quenching, and binding energy models were developed and applied to the compounds.   Finally, a two-dimensional readout system was designed and constructed. The capabilities of the system were evaluated using the OSL of NaMgF3:Eu and NaMgF3:Mn. Sensitivities to doses from < 10 mGy to > 1 Gy were obtained along with sub-millimetre spatial resolutions.</p>

SPATIAL XPM-PAIRED SOLITONS IN NONLINEAR METAMATERIALS

2013 ◽  
Vol 22 (01) ◽  
pp. 1350009
Author(s):  
ANLE FANG ◽  
YUANJIANG XIANG ◽  
BINXIAN ZHUANG ◽  
LEYONG JIANG ◽  
XIAOYU DAI ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fibers ◽  
Function Method ◽  
Hyperbolic Function ◽  
Nonlinear Polarization ◽  
Dark Solitons ◽  
Nonlinear Metamaterials ◽  
Theoretical Predictions ◽  
Hyperbolic Function Method ◽  
Propagation Properties

We investigate spatial XPM-paired solitons in nonlinear metamaterials (MMs) based on the (1 + 1)-dimensional coupled nonlinear Schrodinger equation (NLSE) describing the co-propagation of two optical beams of different frequencies in the MM with a Kerr-type nonlinear polarization. Three types of XPM-paired solitons including bright-bright, bright-dark and dark-dark solitons for different combination of the signs of refractive index experienced by the two beams, respectively, are obtained by using a generalized hyperbolic function method, which makes the temporal XPM-paired solitons in optical fibers find their spatial counterparts in MMs. Numerical simulations are performed to confirm the theoretical predictions and further identify the propagation properties of the spatial XPM-paired solitons in MMs described by Drude model.

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