An Interfacial Tracking Method for Ultrashort Pulse Laser Melting and Resolidification of a Thin Metal Film

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Yuwen Zhang ◽  
J. K. Chen
Keyword(s):  
Metal Film ◽  
Laser Energy ◽  
Film Surface ◽  
Iterative Solution ◽  
Coupling Factor ◽  
Solution Procedure ◽  
Thin Metal Film ◽  
Solidification Temperature ◽  
Ultrashort Pulse Laser ◽  
Tracking Method

An interfacial tracking method was developed to model rapid melting and resolidification of a freestanding metal film subject to an ultrashort laser pulse. The laser energy was deposited to the electrons near thin film surface, and subsequently diffused into a deeper part of the electron gas and transferred to the lattice. The energy equations for the electron and lattice were coupled through an electron-lattice coupling factor. Melting and resolidification were modeled by considering the interfacial energy balance and nucleation dynamics. An iterative solution procedure was employed to determine the elevated melting temperature and depressed solidification temperature in the ultrafast phase-change processes. The predicted surface lattice temperature, interfacial location, interfacial temperature, and interfacial velocity were compared with those obtained by an explicit enthalpy model. The effects of the electron thermal conductivity models, ballistic range, and laser fluence on the melting and resolidification were also investigated.

An Interfacial Tracking Method for Ultrashort Pulse Laser Melting and Resolidification of a Thin Metal Film

2007 ◽  
Author(s):  
Yuwen Zhang ◽  
J. K. Chen
Keyword(s):  
Metal Film ◽  
Laser Energy ◽  
Film Surface ◽  
Iterative Solution ◽  
Coupling Factor ◽  
Solution Procedure ◽  
Thin Metal Film ◽  
Free Standing ◽  
Solidification Temperature ◽  
Tracking Method

An interfacial tracking method is developed to model rapid melting and resolidification of a free-standing metal film subject to an ultrashort laser pulse. The laser energy is deposited to the electrons near thin film surface, and subsequently diffused into deeper part of the electron gas and transferred to the lattice. The energy equations for the electron and lattice are coupled through an electron-lattice coupling factor. Melting and resolidification are modeled by considering the interfacial energy balance and nucleation dynamics. An iterative solution procedure is employed to determine the elevated melting temperature and depressed solidification temperature in the ultrafast phase-change process. The predicted surface lattice temperature, interfacial location, interfacial temperature, and interfacial velocity are compared with those obtained by an explicit enthalpy model. The effects of the electron thermal conductivity models, ballistic range, and laser fluence on the melting and resolidification are also investigated.

Laser-Assisted and Roller-Based Nano-Imprinting Technologies and Their Applications

2007 ◽  
Author(s):  
Yung-Chun Lee ◽  
Cheng-Yu Chiu ◽  
Chun-Hung Chen ◽  
Chun-Shiang Chen
Keyword(s):  
Laser Heating ◽  
Metal Film ◽  
Laser Energy ◽  
Experimental Testing ◽  
Pulsed Laser ◽  
Experimental Tests ◽  
Thin Metal Film ◽  
Large Area ◽  
Contact Printing ◽  
Continuous Type

Nano-imprinting lithography (NIL) has been developed over 15 years and has shown its great potentials for nanopatterning and nano-fabrication. In this paper, new ideas on improving current nano-imprinting methods have been proposed and preliminary experimental tests are carried out. These proposed nano-imprinting methods are all based on the utilization of pulsed laser sources, either in UV or IR region, and can be easily implemented into a roller-based configuration, which is more effective and much faster than conventional planar type nano-imprinting methods. First of all, based on the Laser Assisted Direct Imprinting (LADI) method proposed in 2002, a modified roller-based LADI method is developed by applying a cylindrical quartz roller for mechanically loading as well as for optically focusing of a deep UV laser beam into a line. This modification not only fulfills a continuous type of LADI process but also more efficiently utilizes the laser energy so that large-area LADI is possible. Experimental testing demonstrates an imprinting rate of 3∼10 cm2/min. Secondly, a new nano-imprinting lithography based on pulsed infrared laser heating is proposed and demonstrated. It utilizes the partial transparency of silicon crystals at IR spectrum to heat up the photo-resist layer. Possible improvements and applications on this IR-NIL will be addressed. Finally, a new method of direct contact printing and patterning of a thin metal film on silicon substrate based on the idea of nano-imprinting is presented. This method combines the effects of loaded contact pressure and IR pulsed laser heating at the metal-film/substrate interface to form a stronger bonding between them, and therefore complete the direct pattern transferring of metal film on substrate. Good experimental results are observed and possible applications will be discussed.

scholarly journals Observing and controlling a Tamm plasmon at the interface with a metasurface

Nanophotonics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 897-903 ◽  
Author(s):  
Oleksandr Buchnev ◽  
Alexandr Belosludtsev ◽  
Victor Reshetnyak ◽  
Dean R. Evans ◽  
Vassili A. Fedotov
Keyword(s):  
Liquid Crystal ◽  
Metal Film ◽  
Near Infrared ◽  
Thin Metal Film ◽  
Outer Side ◽  
Spectral Position ◽  
External Perturbations ◽  
Dielectric Mirror ◽  
Wavelength Scale ◽  
Sub Wavelength

AbstractWe demonstrate experimentally that Tamm plasmons in the near infrared can be supported by a dielectric mirror interfaced with a metasurface, a discontinuous thin metal film periodically patterned on the sub-wavelength scale. More crucially, not only do Tamm plasmons survive the nanopatterning of the metal film but they also become sensitive to external perturbations as a result. In particular, by depositing a nematic liquid crystal on the outer side of the metasurface, we were able to red shift the spectral position of Tamm plasmon by 35 nm, while electrical switching of the liquid crystal enabled us to tune the wavelength of this notoriously inert excitation within a 10-nm range.

scholarly journals Self-updated four-node finite element using deep learning

2021 ◽  
Author(s):  
Jaeho Jung ◽  
Hyungmin Jun ◽  
Phill-Seung Lee
Keyword(s):  
Finite Element ◽  
Deep Learning ◽  
Iterative Solution ◽  
Solution Procedure ◽  
Element Formulation ◽  
Zero Energy ◽  
Energy Mode ◽  
Bending Modes ◽  
Solution Accuracy ◽  
Iterative Solution Procedure

AbstractThis paper introduces a new concept called self-updated finite element (SUFE). The finite element (FE) is activated through an iterative procedure to improve the solution accuracy without mesh refinement. A mode-based finite element formulation is devised for a four-node finite element and the assumed modal strain is employed for bending modes. A search procedure for optimal bending directions is implemented through deep learning for a given element deformation to minimize shear locking. The proposed element is called a self-updated four-node finite element, for which an iterative solution procedure is developed. The element passes the patch and zero-energy mode tests. As the number of iterations increases, the finite element solutions become more and more accurate, resulting in significantly accurate solutions with a few iterations. The SUFE concept is very effective, especially when the meshes are coarse and severely distorted. Its excellent performance is demonstrated through various numerical examples.

Self-Ordered Vicinal-Surface-Like Nanosteps at the Thin Metal-Film/Substrate Interface

2012 ◽  
Vol 116 (22) ◽  
pp. 12149-12155 ◽  
Author(s):  
Shirly Borukhin ◽  
Cecile Saguy ◽  
Maria Koifman ◽  
Boaz Pokroy
Keyword(s):  
Metal Film ◽  
Thin Metal Film ◽  
Thin Metal ◽  
Vicinal Surface ◽  
Substrate Interface ◽  
Film Substrate
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