scholarly journals Dynamics of Ripple Formation in Sputter Erosion: Nonlinear Phenomena

1999 ◽  
Vol 83 (17) ◽  
pp. 3486-3489 ◽  
Author(s):  
S. Park ◽  
B. Kahng ◽  
H. Jeong ◽  
A.-L. Barabási
Keyword(s):  
Nonlinear Phenomena ◽  
Ripple Formation ◽  
Sputter Erosion

Nonlinear Ripple Formation in Sputter Erosion

1999 ◽  
Vol 585 ◽  
Author(s):  
A.-L. Barabási ◽  
B. Kahng ◽  
H. Jeong ◽  
S. Park
Keyword(s):  
Surface Morphology ◽  
Linear Theory ◽  
Characteristic Time ◽  
Nonlinear Effects ◽  
Morphological Features ◽  
Ripple Formation ◽  
Morphological Transitions ◽  
Sputter Erosion ◽  
Short Times

AbstractWe investigate the morphological features of sputter eroded surfaces, demonstrating that while at short times ripple formation is described by the linear theory, after a characteristic time the nonlinear terms determine the surface morphology. We also show that the morphological transitions induced by the nonlinear effects can be detected by monitoring the surface width and the erosion velocity.

scholarly journals Ripple Formation during Oblique Angle Etching

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 272
Author(s):  
Mehmet F. Cansizoglu ◽  
Mesut Yurukcu ◽  
Tansel Karabacak
Keyword(s):  
Plasma Etching ◽  
Incidence Angle ◽  
Incident Beam ◽  
Root Mean Square Roughness ◽  
Sticking Coefficient ◽  
Oblique Angle ◽  
Nano Fabrication ◽  
Ripple Formation ◽  
Rapid Formation ◽  
Roughness Analysis

Chemical removal of materials from the surface is a fundamental step in micro- and nano-fabrication processes. In conventional plasma etching, etchant molecules are non-directional and perform a uniform etching over the surface. However, using a highly directional obliquely incident beam of etching agent, it can be possible to engineer surfaces in the micro- or nano- scales. Surfaces can be patterned with periodic morphologies like ripples and mounds by controlling parameters including the incidence angle with the surface and sticking coefficient of etching particles. In this study, the dynamic evolution of a rippled morphology has been investigated during oblique angle etching (OAE) using Monte Carlo simulations. Fourier space and roughness analysis were performed on the resulting simulated surfaces. The ripple formation was observed to originate from re-emission and shadowing effects during OAE. Our results show that the ripple wavelength and root-mean-square roughness evolved at a more stable rate with accompanying quasi-periodic ripple formation at higher etching angles (θ > 60°) and at sticking coefficient values (Sc) 0.5 ≤ Sc ≤ 1. On the other hand, smaller etching angle (θ < 60°) and lower sticking coefficient values lead to a rapid formation of wider and deeper ripples. This result of this study can be helpful to develop new surface patterning techniques by etching.

scholarly journals High Field Single- to Few-Cycle THz Generation with Lithium Niobate

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 183
Author(s):  
Xing Zhu ◽  
David R. Bacon ◽  
Julien Madéo ◽  
Keshav M. Dani
Keyword(s):  
Lithium Niobate ◽  
Condensed Matter ◽  
High Harmonic ◽  
Nonlinear Spectroscopy ◽  
Optical Rectification ◽  
Phase Matching ◽  
Nonlinear Phenomena ◽  
Generation Efficiency ◽  
Basic Principles ◽  
Thz Generation

The transient terahertz (THz) pulse with high peak field has become an important tool for matter manipulation, enabling many applications such as nonlinear spectroscopy, particle acceleration, and high harmonic generation. Among the widely used THz generation techniques, optical rectification in lithium niobate (LN) has emerged as a powerful method to achieve high fields at low THz frequencies, suitable to exploring novel nonlinear phenomena in condensed matter systems. In this review, we focus on introducing single- to few-cycle THz generation in LN, including the basic principles, techniques, latest developments, and current limitations. We will first discuss the phase matching requirements of LN, which leads to Cherenkov-like radiation, and the tilted pulse front (TPF) technique. Emphasis will be put on the TPF technique, which has been shown to improve THz generation efficiency, but still has many limitations. Different geometries used to produce continuous and discrete TPF will be systematically discussed. We summarize the advantages and limitations of current techniques and future trends.

scholarly journals Nondegenerate Bright Solitons in Coupled Nonlinear Schrödinger Systems: Recent Developments on Optical Vector Solitons

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 258
Author(s):  
S. Stalin ◽  
R. Ramakrishnan ◽  
M. Lakshmanan
Keyword(s):  
Propagation Constant ◽  
Short Wave ◽  
Nonlinear Phenomena ◽  
Bilinear Method ◽  
Nonlinear Schrödinger ◽  
Bright Solitons ◽  
Nonlinear Schrödinger Systems ◽  
Recent Developments ◽  
Potential Applications ◽  
Photorefractive Materials

Nonlinear dynamics of an optical pulse or a beam continue to be one of the active areas of research in the field of optical solitons. Especially, in multi-mode fibers or fiber arrays and photorefractive materials, the vector solitons display rich nonlinear phenomena. Due to their fascinating and intriguing novel properties, the theory of optical vector solitons has been developed considerably both from theoretical and experimental points of view leading to soliton-based promising potential applications. Mathematically, the dynamics of vector solitons can be understood from the framework of the coupled nonlinear Schrödinger (CNLS) family of equations. In the recent past, many types of vector solitons have been identified both in the integrable and non-integrable CNLS framework. In this article, we review some of the recent progress in understanding the dynamics of the so called nondegenerate vector bright solitons in nonlinear optics, where the fundamental soliton can have more than one propagation constant. We address this theme by considering the integrable two coupled nonlinear Schrödinger family of equations, namely the Manakov system, mixed 2-CNLS system (or focusing-defocusing CNLS system), coherently coupled nonlinear Schrödinger (CCNLS) system, generalized coupled nonlinear Schrödinger (GCNLS) system and two-component long-wave short-wave resonance interaction (LSRI) system. In these models, we discuss the existence of nondegenerate vector solitons and their associated novel multi-hump geometrical profile nature by deriving their analytical forms through the Hirota bilinear method. Then we reveal the novel collision properties of the nondegenerate solitons in the Manakov system as an example. The asymptotic analysis shows that the nondegenerate solitons, in general, undergo three types of elastic collisions without any energy redistribution among the modes. Furthermore, we show that the energy sharing collision exhibiting vector solitons arises as a special case of the newly reported nondegenerate vector solitons. Finally, we point out the possible further developments in this subject and potential applications.

scholarly journals Ultrasonic actuation of a fine-needle improves biopsy yield

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emanuele Perra ◽  
Eetu Lampsijärvi ◽  
Gonçalo Barreto ◽  
Muhammad Arif ◽  
Tuomas Puranen ◽  
...  
Keyword(s):  
Needle Biopsy ◽  
Fine Needle Biopsy ◽  
Current Medical ◽  
Nonlinear Phenomena ◽  
Fine Needle ◽  
The Past ◽  
Minimally Invasive Surgical ◽  
Nonlinear Ultrasonics ◽  
Or Gene ◽  
Medical Needle

AbstractDespite the ubiquitous use over the past 150 years, the functions of the current medical needle are facilitated only by mechanical shear and cutting by the needle tip, i.e. the lancet. In this study, we demonstrate how nonlinear ultrasonics (NLU) extends the functionality of the medical needle far beyond its present capability. The NLU actions were found to be localized to the proximity of the needle tip, the SonoLancet, but the effects extend to several millimeters from the physical needle boundary. The observed nonlinear phenomena, transient cavitation, fluid streams, translation of micro- and nanoparticles and atomization, were quantitatively characterized. In the fine-needle biopsy application, the SonoLancet contributed to obtaining tissue cores with an increase in tissue yield by 3–6× in different tissue types compared to conventional needle biopsy technique using the same 21G needle. In conclusion, the SonoLancet could be of interest to several other medical applications, including drug or gene delivery, cell modulation, and minimally invasive surgical procedures.

scholarly journals Influence of Elastomeric Bearings in Tension on the Seismic Performance of Base-Isolated r.c. Buildings

2020 ◽  
Vol 11 (1) ◽  
pp. 82
Author(s):  
Fabio Mazza ◽  
Mirko Mazza
Keyword(s):  
Base Isolation ◽  
Nonlinear Models ◽  
Vertical Component ◽  
Computer Code ◽  
Nonlinear Phenomena ◽  
Isolation System ◽  
Elastomeric Bearings ◽  
Near Fault ◽  
Base Isolation System ◽  
Near Fault Earthquakes

Elastomeric bearings are commonly used in base-isolation systems to protect the structures from earthquake damages. Their design is usually developed by using nonlinear models where only the effects of shear and compressive loads are considered, but uncertainties still remain about consequences of the tensile loads produced by severe earthquakes like the near-fault ones. The present work aims to highlight the relapses of tension on the response of bearings and superstructure. To this end, three-, seven- and ten-storey r.c. framed buildings are designed in line with the current Italian seismic code, with a base-isolation system constituted of High-Damping-Rubber Bearings (HDRBs) designed for three values of the ratio between the vertical and horizontal stiffnesses. Experimental and analytical results available in literature are used to propose a unified nonlinear model of the HDRBs, including cavitation and post-cavitation of the elastomer. Nonlinear incremental dynamic analyses of the test structures are carried out using a homemade computer code, where other models of HDRBs considering only some nonlinear phenomena are implemented. Near-fault earthquakes with comparable horizontal and vertical components, prevailing horizontal component and prevailing vertical component are considered as seismic input. Numerical results highlight that a precautionary estimation of response parameters of the HDRBs is attained referring to the proposed model, while its effects on the nonlinear response of the superstructure are less conservative.

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