Gap solitons supported by an optical lattice in biased photorefractive crystals having both the linear and quadratic electro-optic effect

2020 ◽  
Vol 75 (8) ◽  
pp. 749-756
Author(s):  
Aavishkar Katti ◽  
Chittaranjan P. Katti
Keyword(s):  
Band Gap ◽  
Optical Lattice ◽  
Propagation Constant ◽  
Gap Soliton ◽  
Electro Optic ◽  
Quadratic Nonlinearities ◽  
Existence And Stability ◽  
Gap Solitons ◽  
Finite Band ◽  
First Time

AbstractWe investigate the existence and stability of gap solitons supported by an optical lattice in biased photorefractive (PR) crystals having both the linear and quadratic electro-optic effect. Such PR crystals have an interesting interplay between the linear and quadratic nonlinearities. Gap solitons are predicted for the first time in such novel PR media. Taking a relevant example (PMN-0.33PT), we find that the gap solitons in the first finite bandgap are single humped, positive and symmetric solitons while those in the second finite band gap are antisymmetric and double humped. The power of the gap soliton depends upon the value of the axial propagation constant. We delineate three power regimes and study the gap soliton profiles in each region. The gap solitons in the first finite band gap are not linearly stable while those in the second finite band gap are found to be stable against small perturbations. We study their stability properties in detail throughout the finite band gaps. The interplay between the linear and quadratic electro-optic effect is studied by investigating the spatial profiles and stability of the gap solitons for different ratios of the linear and quadratic nonlinear coefficients.

SOLITON ON THE SEMI-INFINITE BAND GAP OF BEC IN AN OPTICAL LATTICE

2011 ◽  
Vol 25 (06) ◽  
pp. 781-793 ◽  
Author(s):  
D. L. WANG ◽  
X. H. YAN
Keyword(s):  
Band Gap ◽  
Optical Lattice ◽  
Stable Condition ◽  
Multiple Scale ◽  
Experimental Protocol ◽  
One Dimensional ◽  
Energy Gaps ◽  
Gap Soliton ◽  
Gap Solitons ◽  
Bose Einstein

By developing a multiple-scale method, we study analytically the dynamics of the soliton inside the semi-infinite band gap (SIBG) of quasi-one-dimensional Bose–Einstein condensates trapped in an optical lattice. In the linear case, a stable condition of soliton formation is obtained. For a weak nonlinearity, whether there occurs a spatially propagating or localized gap soliton is determined by the lattice depth. Meanwhile, we predict the existence of the dark (bright) gap solitons for the repulsive (attractive) interactions in the SIBG, different from that of the gap solitons in other energy gaps. And the collision of two dark (or bright) solitons is nearly elastic under a safe range of atomic numbers. An experimental protocol is further designed for observing these phenomena.

Multi-peak gap solitons in PT-symmetric optical lattice in the form of superlattice and dual superlattice

2015 ◽  
Vol 24 (02) ◽  
pp. 1550024 ◽  
Author(s):  
Zhen Li ◽  
Shuang Shi ◽  
Xiao-Ping Ren ◽  
Hong Wang
Keyword(s):  
Refractive Index ◽  
Linear Stability ◽  
Imaginary Part ◽  
Optical Lattice ◽  
Power Flow ◽  
Periodic Lattice ◽  
Spectra Analysis ◽  
Existence And Stability ◽  
Gap Solitons ◽  
Simulation Results

We report the existence and stability of multi-peak gap solitons in PT-symmetric optical lattice with the real part of the refractive index in the form of superlattice and the imaginary part having two different profiles; one with odd periodic lattice and the second with odd superlattice supported by a defocusing nonlinearity. Linear-stability spectra analysis and simulation results show that they can be stable in the scope of the first gap. The profile of the multi-peak solitons and the power-flow vector is found to be different from those of one cycle lattice.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

scholarly journals Band-Gap Solitons in Nonlinear Photonic Crystal Waveguides and Their Application for Functional All-Optical Logic Gating

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 250
Author(s):  
Vakhtang Jandieri ◽  
Ramaz Khomeriki ◽  
Tornike Onoprishvili ◽  
Daniel Erni ◽  
Levan Chotorlishvili ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Band Gap ◽  
Crystalline Silicon ◽  
Logic Gates ◽  
Photonic Crystal Waveguides ◽  
Optical Logic ◽  
Logical Operation ◽  
Pulse Envelope ◽  
Gap Soliton ◽  
All Optical

This review paper summarizes our previous findings regarding propagation characteristics of band-gap temporal solitons in photonic crystal waveguides with Kerr-type nonlinearity and a realization of functional and easily scalable all-optical NOT, AND and NAND logic gates. The proposed structure consists of a planar air-hole type photonic crystal in crystalline silicon as the nonlinear background material. A main advantage of proposing the gap-soliton as a signal carrier is that, by operating in the true time-domain, the temporal soliton maintains a stable pulse envelope during each logical operation. Hence, multiple concatenated all-optical logic gates can be easily realized paving the way to multiple-input ultrafast full-optical digital signal processing. In the suggested setup, due to the gap-soliton features, there is no need to amplify the output signal after each operation which can be directly used as a new input signal for another logical operation. The efficiency of the proposed logic gates as well as their scalability is validated using our original rigorous theoretical formalism confirmed by full-wave computational electromagnetics.

Nano-Photonic Electro-Optic Polymer Modulator based on Photonic Band Gap Engineering

2009 ◽  
Author(s):  
Xiaolong Wang ◽  
Swapnajit Chakravarty ◽  
Boem Suk Lee ◽  
Cheyun Lin ◽  
Jingdong Luo ◽  
...  
Keyword(s):  
Band Gap ◽  
Photonic Band Gap ◽  
Band Gap Engineering ◽  
Electro Optic ◽  
Photonic Band

scholarly journals Development of the Morphology and the Band Gap Energy of Co–Si Nanofibers by Inserting Zirconium and Titanium with Dual Anions Intercalation Process

2019 ◽  
Vol 9 (22) ◽  
pp. 4775 ◽  
Author(s):  
Osama Saber ◽  
Nagih M. Shaalan ◽  
Aya Osama ◽  
Adil Alshoaibi
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Optical Materials ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Intercalation Process ◽  
Trivalent Cations ◽  
Optical Applications ◽  
Double Hydroxides ◽  
First Time

The plate-like structure is the most familiar morphology for conventional layered double hydroxides (LDHs) in case their structures consist of divalent and trivalent cations in their layers. In this study, nanofibers and nanoneedles of Co–Si LDHs were prepared for the first time. By the inclusion of zirconium inside the nanolayers of LDH structures, their plates were formed and transformed to nanofibers. These nanofibers were modified by the insertion of titanium to build again plate-like morphology for the LDH structure. This morphology controlling was studied and explained by a dual anions intercalation process. The optical properties of Co–Si LDHs indicated that the incorporation of zirconium within their nanolayers decreased the band gap energy from 4.4 eV to 2.9 eV. Following the same behavior, the insertion of titanium besides zirconium within the nanolayers of Co–Si LDHs caused a further reduction in the band gap energy, which became 2.85 eV. Although there is no data for the optical properties of Co–Si LDHs in the literature, it is interesting to observe the low band gap energy for Co–Si LDHs to become more suitable for optical applications. These results concluded that the reduction of the band gap energy and the formation of nanofibers introduce new optical materials for developing and designing optical nanodevices.

Spontaneous emission inhibition from a driven four-level atom in a photonic band gap material

2007 ◽  
Vol 85 (9) ◽  
pp. 981-994
Author(s):  
H Zhang ◽  
G Q Liu ◽  
H Z Zhang
Keyword(s):  
Band Gap ◽  
Spontaneous Emission ◽  
Quantum Interference ◽  
Photonic Band Gap ◽  
Coupling Model ◽  
Interference Effects ◽  
Level Atom ◽  
Photonic Band Gap Material ◽  
First Time ◽  
Photonic Band

Two models (an upper levels coupling model and a lower levels coupling model) of a four-level atom embedded in a double-band photonic crystal are adopted. The effect of spontaneous emission cancellation of such systems embedded in different reservoirs are investigated. Especially, the "trapping conditions" of such systems in photonic band gap (PBG) reservoirs are discussed for the first time. We also investigate the different quantum interference effects of the lower levels coupling model embedded in an isotropic PBG reservoir. It is interesting that when the trapping conditions are fulfilled, the additional peaks, which result from the contribution of the additional singularities of Laplace transform of the delayed Green function of the isotropic PBG modes, are eliminated.PACS Nos.: 42.50.Gy, 42.50.Ct, 42.70.Qs

Interaction-determined sensitization photodegradation of dye complexes by boron nitride under visible light irradiation: experimental and theoretical studies

2020 ◽  
Vol 44 (22) ◽  
pp. 9238-9247
Author(s):  
Xin Ji ◽  
Yong Guo ◽  
Shugui Hua ◽  
Huiyan Li ◽  
Sunchen Zhang
Keyword(s):  
Boron Nitride ◽  
Visible Light ◽  
Band Gap ◽  
Visible Light Irradiation ◽  
Wide Band ◽  
Light Irradiation ◽  
Theoretical Studies ◽  
Wide Band Gap ◽  
First Time ◽  
Experimental And Theoretical Studies

In this paper, the sensitization photodegradation of single and mixed dyes by wide band gap boron nitride (BN, 3.94 eV) under visible light irradiation has been investigated for the first time.

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