scholarly journals Polarization-selected nonlinearity transition in gold dolmens coupled to an epsilon-near-zero material

Nanophotonics ◽  
2020 ◽  
Vol 9 (16) ◽  
pp. 4839-4851
Author(s):  
Xinxiang Niu ◽  
Xiaoyong Hu ◽  
Quan Sun ◽  
Cuicui Lu ◽  
Yuanmu Yang ◽  
...  
Keyword(s):  
Optical Materials ◽  
Ultrafast Lasers ◽  
Optical Computing ◽  
Coupled System ◽  
Optical Nonlinearity ◽  
Natural Material ◽  
Practical Applications ◽  
System A ◽  
Nonlinear Performance ◽  
Epsilon Near Zero

AbstractNonlinear optical materials are cornerstones of modern optics including ultrafast lasers, optical computing, and harmonic generation. The nonlinear coefficients of optical materials suffer from limitations in strength and bandwidth. Also, the nonlinear performance is typically monotonous without polarization selectivity, and to date, no natural material has been found to possess nonlinear coefficients with positive or negative signs simultaneously at a specific wavelength, all of which impede practical applications in the specific scenario. Here, we realize broadband large optical nonlinearity accompanied with ultrafast dynamics in a coupled system composed of gold dolmens and an epsilon-near-zero material for dual orthogonal polarizations simultaneously. The system also shows the polarization-selected nonlinearity transition properties, where the sign of the optical nonlinear refractive indexes can be converted via polarization switching. This guarantees active transitions from self-focusing to self-defocusing by polarization rotation without tuning wavelength in practical utilizations. The measured nonlinear refractive index and susceptibility demonstrate more than three orders of magnitude enhancement over a 400-nm-bandwidth compared with the constituents, while maintaining the sub-1 ps time response. The realized enhanced, ultrafast response, and the polarization tunability ensure the designed system a promising platform for the development of integrated ultrafast laser sources, all-optical circuits and quantum chips.

scholarly journals Polarization-Independent Large Third-Order-Nonlinearity of Orthogonal Nanoantennas Coupled to an Epsilon-Near-Zero Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3424
Author(s):  
Wenjuan Shi ◽  
Hongjun Liu ◽  
Zhaolu Wang
Keyword(s):  
Optical Nonlinearity ◽  
Optical Signal ◽  
Orthogonal Polarization ◽  
Absolute Maximum ◽  
Strong Nonlinearity ◽  
Third Order ◽  
Highly Nonlinear ◽  
All Optical ◽  
Nonlinear Performance ◽  
Epsilon Near Zero

The nonlinear optical response of common materials is limited by bandwidth and energy consumption, which impedes practical application in all-optical signal processing, light detection, harmonic generation, etc. Additionally, the nonlinear performance is typically sensitive to polarization. To circumvent this constraint, we propose that orthogonal nanoantennas coupled to Al-doped zinc oxide (AZO) epsilon-near-zero (ENZ) material show a broadband (~1000 nm bandwidth) large optical nonlinearity simultaneously for two orthogonal polarization states. The absolute maximum value of the nonlinear refractive index n2 is 7.65 cm2∙GW−1, which is 4 orders of magnitude larger than that of the bare AZO film and 7 orders of magnitude larger than that of silica. The coupled structure not only realizes polarization independence and strong nonlinearity, but also allows the sign of the nonlinear response to be flexibly tailored. It provides a promising platform for the realization of ultracompact, low-power, and highly nonlinear all-optical devices on the nanoscale.

scholarly journals Stability of time-delay systems via Lyapunov functions

2002 ◽  
Vol 8 (3) ◽  
pp. 197-205 ◽  
Author(s):  
Carlos F. Alastruey ◽  
Manuel de la Sen
Keyword(s):  
Lyapunov Function ◽  
Lyapunov Functions ◽  
A Priori ◽  
Original System ◽  
Delay Systems ◽  
Multivariable Systems ◽  
Time Delay Systems ◽  
Input Output ◽  
Practical Applications ◽  
System A

In this paper, a Lyapunov function candidate is introduced for multivariable systems with inner delays, without assuminga prioristability for the nondelayed subsystem. By using this Lyapunov function, a controller is deduced. Such a controller utilizes an input–output description of the original system, a circumstance that facilitates practical applications of the proposed approach.

scholarly journals The Basic Architecture of the System with the A-GNSS Receiver

2019 ◽  
Vol 292 ◽  
pp. 04010
Author(s):  
Lucjan Setlak ◽  
Rafał Kowalik
Keyword(s):  
Mathematical Model ◽  
Research Literature ◽  
Navigation Systems ◽  
Practical Applications ◽  
Gnss Receiver ◽  
System A ◽  
System Solution ◽  
Specific Object ◽  
Mobile Receiver ◽  
Gps System

The paper presents the results of obtained research defining the accuracy of determining the position of a specific object (aircraft, UAV), equipped with a mobile receiver operating the navigation system A-GNSS. The Assisted GNSS technology is designed to improve the performance of the GNSS receiver by reducing the time needed for the receiver to calculate its location. It also increases the sensitivity of the received signal by the receiver, as a result, the accuracy of the determined position of a specific object can be improved. Thanks to its application, the radio-navigation receiver becomes compatible with the requirements of current standards, and what is associated with it this kind of technology has become an important part of the cellular industry. The aim of the article is to examine the solution of A-GPS system and to demonstrate its effectiveness in the process of determining the position of the UAV object. The paper presents aspects of the functionality of the A-GPS system solution work, mathematical model of object position determination using A-GNSS system and discusses the technology that is used for the integration of navigation systems with cellular network. In the final part of the work, based on the analysis of the research literature, the presented mathematical model and simulations, conclusions were formulated, which are reflected in practical applications.

scholarly journals Breathing dissipative solitons in mode-locked fiber lasers

2019 ◽  
Vol 5 (11) ◽  
pp. eaax1110 ◽  
Author(s):  
Junsong Peng ◽  
Sonia Boscolo ◽  
Zihan Zhao ◽  
Heping Zeng
Keyword(s):  
Ultrafast Lasers ◽  
Laser Cavity ◽  
Mode Locking ◽  
Oscillatory Behavior ◽  
Dissipative Systems ◽  
Stationary Mode ◽  
Practical Applications ◽  
Fast Detection ◽  
Dissipative Solitons ◽  
Laser Sources

Dissipative solitons are self-localized coherent structures arising from the balance between energy supply and dissipation. Besides stationary dissipative solitons, there are dynamical ones exhibiting oscillatory behavior, known as breathing dissipative solitons. Substantial interest in breathing dissipative solitons is driven by both their fundamental importance in nonlinear science and their practical applications, such as in spectroscopy. Yet, the observation of breathers has been mainly restricted to microresonator platforms. Here, we generate breathers in a mode-locked fiber laser. They exist in the laser cavity under the pump threshold of stationary mode locking. Using fast detection, we are able to observe the temporal and spectral evolutions of the breathers in real time. Breathing soliton molecules are also observed. Breathers introduce a new regime of mode locking into ultrafast lasers. Our findings may contribute to the design of advanced laser sources and open up new possibilities of generating breathers in various dissipative systems.

scholarly journals Lateral vibration control of a shafting-hull coupled system with electromagnetic bearings

2018 ◽  
Vol 38 (1) ◽  
pp. 154-167 ◽  
Author(s):  
Hui Qin ◽  
Hongbo Zheng ◽  
Wenyuan Qin ◽  
Zhiyi Zhang
Keyword(s):  
Frequency Response ◽  
Acoustic Radiation ◽  
Synthesis Method ◽  
Coupled System ◽  
Lateral Vibration ◽  
Vibration Transmission ◽  
Lateral Vibrations ◽  
System A ◽  
Vibration Responses ◽  
Stiffness And Damping

In order to suppress lateral vibration transmission and reduce acoustic radiation of a shafting-hull coupled system, a new approach using electromagnetic bearings in the shafting system is proposed. The dynamic characteristics of the electromagnetic bearings, especially the equivalent stiffness and damping as well as the applicable scope of linearization of the electromagnetic bearings, are analysed at first. With the equivalent parameters, a dynamic model of the shafting-hull coupled system is established subsequently by using the frequency response synthesis method to derive frequency response functions associated with the lateral vibrations. Finally, the influence of the control parameters of the electromagnetic bearings on vibration transmission in the shafting-hull system is studied. Analysis results indicate that lateral vibration responses are suppressed significantly when electromagnetic bearings are introduced into the shafting-hull system, and as a result, sound radiation of the system is reduced, which demonstrates that the proposed approach is effective in controlling vibration transmission in the shafting system.

Seismic Control of Structures Using Sloped Bottom Tuned Liquid Damper

2019 ◽  
Vol 19 (09) ◽  
pp. 1950096 ◽  
Author(s):  
Amiya Ranjan Pandit ◽  
Kishore Chandra Biswal
Keyword(s):  
Coupled System ◽  
Structural Equations ◽  
Earthquake Ground Motion ◽  
Tuned Liquid Damper ◽  
Seismic Control ◽  
Structure Response ◽  
Quadrilateral Elements ◽  
System A ◽  
Average Acceleration ◽  
Fluid Equations

Tuned liquid damper (TLD) as an economical passive damper has gained importance because of its efficiency in suppressing the undesirable motion of a structure due to devastating earthquakes when it is rigidly attached to the structure. This phenomenon has been studied previously, but mostly limited to rectangular- or cylindrical-shaped TLD. The present study is aimed at determining the potential of the sloped bottom tuned liquid damper to suppress the unwanted vibration of the structure subjected to earthquake ground motion. Three different earthquake ground motions characterized by low-, intermediate- and high-frequency contents are selected for the dynamic analysis of the TLD–structure coupled system. A parametric study on the sloped bottom TLD and its interaction with the sustaining structural system is conducted. The structural equations, which are coupled with fluid equations, are solved by the Newmark-[Formula: see text] method with average acceleration, while the fluid equations are solved using velocity potential-based finite element method. The liquid domain in the TLD is comprised of a combination of three-node triangular and four-node quadrilateral elements. The result shows the reduction in structure response is significant with less amount of water in sloped bottom TLD rather than rectangular TLD.

Angiotensin II decreases system A amino acid transporter activity in human placental villous fragments through AT1 receptor activation

2006 ◽  
Vol 291 (5) ◽  
pp. E1009-E1016 ◽  
Author(s):  
Eiji Shibata ◽  
Robert W. Powers ◽  
Augustine Rajakumar ◽  
Frauke von Versen-Höynck ◽  
Marcia J. Gallaher ◽  
...  
Keyword(s):  
Amino Acid ◽  
Angiotensin Ii ◽  
Atpase Activity ◽  
Renin Angiotensin System ◽  
Coupled System ◽  
Receptor Activation ◽  
Isobutyric Acid ◽  
Transport Systems ◽  
System A ◽  
Placental Villi

Reduced transport of amino acids from mother to fetus can lead to fetal intrauterine growth restriction (IUGR). The activities of several amino acid transport systems, including system A, are decreased in placental syncytiotrophoblast of IUGR pregnancies. Na+-K+-ATPase activity provides an essential driving force for Na+-coupled system A transport, is decreased in the placenta of IUGR pregnancies, and is decreased by angiotensin II in several tissues. Several reports have shown activation of the fetoplacental renin-angiotensin system (RAS) in IUGR. We investigated the effect of angiotensin II on placental system A transport and Na+-K+-ATPase activity in placental villi. Placental system A activity in single primary villous fragments was measured as the Na+-dependent uptake of α-(methylamino)isobutyric acid, and Na+/K+ ATPase activity was measured as ouabain-sensitive uptake of 86rubidium. Angiotensin II decreased system A activity in a concentration-dependent fashion (10–500 nmol/l). Angiotensin II type 1 receptor (AT1-R) antagonists losartan and AT1-R anti-peptide blocked the angiotensin II effect, but the angiotensin II type 2 receptor antagonist PD-123319 was without effect. System A activity was not altered by preincubation with AT1-R-independent vasoconstrictors, and antioxidants did not prevent the decrease in activity mediated by angiotensin II. Angiotensin II decreased Na+-K+-ATPase activity by an AT1-R dependent mechanism, and inhibition of Na+-K+-ATPase activity decreased system A activity in a dose-response fashion. These data suggest that angiotensin II, via AT1-R signaling, decreases system A activity by suppressing Na+-K+-ATPase in human placental villi, consistent with possible adverse effects of enhanced placental RAS on fetal growth.

Frequency Based Subsystem Identification Using Hybrid Primal-Dual Formulation

2011 ◽  
Author(s):  
Walter D’Ambrogio ◽  
Annalisa Fregolent
Keyword(s):  
Frequency Response ◽  
Dynamic Balance ◽  
Coupled System ◽  
Response Functions ◽  
Structural System ◽  
Frequency Response Functions ◽  
Dual Formulation ◽  
System A ◽  
Primal Dual

The paper considers the identification of a structural subsystem, starting from the Frequency Response Functions of the assembled system, and from information about the remaining part of the structural system (residual subsystem), i.e. the so called decoupling problem. A possible approach is direct decoupling, which consists in adding to the coupled system a fictitious subsystem which is the negative of the residual subsystem. Starting from the 3-field formulation (dynamic balance, compatibility and equilibrium at the interface), the problem can be solved in a primal or in a dual manner. Compatibility and equilibrium can be required either at coupling DoFs only, or at additional internal DoFs of the residual subsystem. Furthermore DoFs used to enforce equilibrium might be not the same as DoFs used for compatibility: this generates the so called non collocated approach. In this paper, a hybrid primal-dual formulation is applied in combination with collocated and non collocated interface.

Doped Polymers as Third-Order Nonlinear-Optical Materials

1990 ◽  
Vol 214 ◽  
Author(s):  
Mark. G. Kuzyk ◽  
U. C. Paek ◽  
Carl W. Dirk ◽  
Mark P. Andrews
Keyword(s):  
Optical Materials ◽  
Nonlinear Optical ◽  
Polymeric Materials ◽  
Optical Nonlinearity ◽  
Third Order ◽  
Optical Device ◽  
Optical Fiber Devices ◽  
The Status ◽  
Device Applications ◽  
Doped Polymers

ABSTRACTRecently, there has been much interest in doped polymeric materials owing to their suitability for optical device applications.[1] While most of this effort has been centered on poled polymers and their applications to electrooptics, doped polymers are beginning to emerge as a promising material class for all-optical device applications. In this contribution, we discuss the status of doped polymers as third-order optical materials. Particular attention is focused on those properties that make doped polymers attractive as device materials such as optical nonlinearity and loss and their suitability for nonlinear-optical fiber devices.

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