Rod–sphere cluster irradiation with femtosecond laser pulses: cut and paste at the nanoscale

Abstract We report on the irradiation of gold rod–sphere assemblies with ultrashort laser pulses, producing structures that are very difficult to obtain by other methods. The optical response of these assemblies displays several peaks arising from the interaction of the plasmon modes of the individual particles, offering thus great flexibility to control the energy deposited on the individual particles. Judicious selection of the wavelength and fluence of the laser pulses allow fine control over the changes produced: the particles can be melted, welded and/or the organic links cleaved. In this way, it is possible to generate structures “à la carte” with a degree of control unmatched by other synthetic protocols. The method is exemplified with gold nanoparticles, but it can be easily implemented on particles composed of different metals, widening considerably the range of possibilities. The final structures are excellent candidates for surface-enhanced spectroscopies or plasmonic photothermal therapy as they have a very intense electric field located outside the structure, not in the gaps.

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Picosecond Single-Photon and Femtosecond Two-Photon Pulsed Laser Stimulation for IC Characterization and Failure Analysis

ISTFA 2009: Conference Proceedings from the 35th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2009p0268 ◽

2009 ◽

Author(s):

V. Pouget ◽

E. Faraud ◽

K. Shao ◽

S. Jonathas ◽

D. Horain ◽

...

Keyword(s):

Femtosecond Laser ◽

Single Photon ◽

Pulsed Laser ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Ultrashort Laser Pulses ◽

Laser Stimulation ◽

Two Photon ◽

Resolution Improvement ◽

Ultrashort Laser

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.

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High-quality net shape geometries from additively manufactured parts using closed-loop controlled ablation with ultrashort laser pulses

Advanced Optical Technologies ◽

10.1515/aot-2019-0065 ◽

2020 ◽

Vol 9 (1-2) ◽

pp. 101-110 ◽

Cited By ~ 1

Author(s):

Daniel Holder ◽

Artur Leis ◽

Matthias Buser ◽

Rudolf Weber ◽

Thomas Graf

Keyword(s):

Surface Roughness ◽

Closed Loop ◽

High Surface ◽

Laser Pulses ◽

Ultrashort Laser Pulses ◽

Minimum Thickness ◽

High Quality ◽

Surface Optical ◽

The Individual ◽

Ultrashort Laser

AbstractAdditively manufactured parts typically deviate to some extent from the targeted net shape and exhibit high surface roughness due to the size of the powder grains that determines the minimum thickness of the individual slices and due to partially molten powder grains adhering on the surface. Optical coherence tomography (OCT)-based measurements and closed-loop controlled ablation with ultrashort laser pulses were utilized for the precise positioning of the LPBF-generated aluminum parts and for post-processing by selective laser ablation of the excessive material. As a result, high-quality net shape geometries were achieved with surface roughness, and deviation from the targeted net shape geometry reduced by 67% and 63%, respectively.

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Femtosecond Laser Pulses Operation in Crystal under High-Power Diode Pumping

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1101.169 ◽

2015 ◽

Vol 1101 ◽

pp. 169-172

Author(s):

Brij Mohan Kumar Prasad ◽

Amrit Bawankan

Keyword(s):

Beam Quality ◽

Average Power ◽

Visible Region ◽

Laser Pulses ◽

Mode Locking ◽

Femtosecond Laser Pulses ◽

Ultrashort Laser Pulses ◽

Semiconductor Saturable Absorber ◽

Bonding Failure ◽

Ultrashort Laser

We report on a diode laser which is used to pump directly the crystal with a semiconductor saturable absorber allows passive mode locking for the generation of pulses with an average power along with the broadband light by focusing on ultrashort laser pulses into crystal tungstate. The nonuniformity can lead to the crystal and bonding failure. Also model the thermal and structural properties at the various tempeartures to observe the beam quality. Extends the generated spectrum from the infrared to ultraviolet through the visible region, it consists of discrete spatially separated sidebands.

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Fabricating waveguide Bragg gratings (WBGs) in bulk materials using ultrashort laser pulses

Nanophotonics ◽

10.1515/nanoph-2016-0119 ◽

2017 ◽

Vol 6 (5) ◽

pp. 743-763 ◽

Cited By ~ 14

Author(s):

Martin Ams ◽

Peter Dekker ◽

Simon Gross ◽

Michael J. Withford

Keyword(s):

Femtosecond Laser ◽

Ion Beam ◽

Laser Pulses ◽

Bragg Gratings ◽

Femtosecond Laser Pulses ◽

Ultrafast Laser ◽

Ultrashort Laser Pulses ◽

Clean Room ◽

Bulk Materials ◽

Ultrashort Laser

AbstractOptical waveguide Bragg gratings (WBGs) can be created in transparent materials using femtosecond laser pulses. The technique is conducted without the need for lithography, ion-beam fabrication methods, or clean room facilities. This paper reviews the field of ultrafast laser-inscribed WBGs since its inception, with a particular focus on fabrication techniques, WBG characteristics, WBG types, and WBG applications.

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On the importance of initial conditions for excited-state dynamics

Faraday Discussions ◽

10.1039/c8fd00088c ◽

2018 ◽

Vol 212 ◽

pp. 307-330 ◽

Cited By ~ 8

Author(s):

Jiří Suchan ◽

Daniel Hollas ◽

Basile F. E. Curchod ◽

Petr Slavíček

Keyword(s):

Excited State ◽

Initial Conditions ◽

Laser Pulses ◽

Ultrashort Laser Pulses ◽

Electronic Structure Theory ◽

Structure Theory ◽

Classical Trajectories ◽

Ultrashort Laser ◽

Selection Of ◽

Continuum Wave

The vast majority of ab initio excited-state simulations are performed within semiclassical, trajectory-based approaches. Apart from the underlying electronic-structure theory, the reliability of the simulations is controlled by a selection of initial conditions for the classical trajectories. We discuss appropriate choices of initial conditions for simulations of different experimental arrangements: dynamics initiated by continuum-wave (CW) laser fields or triggered by ultrashort laser pulses.

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Localized Electron Evolution Induced by Femtosecond Laser Pulses in Water

10.1115/imece2001/htd-24349 ◽

2001 ◽

Author(s):

C. H. Fan ◽

J. Sun ◽

J. P. Longtin

Keyword(s):

Femtosecond Laser ◽

Electron Density ◽

Inhomogeneous Plasma ◽

Optical Breakdown ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Ultrashort Laser Pulses ◽

Rate Equations ◽

Focal Region ◽

Ultrashort Laser

Abstract Optical breakdown by ultrashort laser pulses in dielectrics presents an efficient method to deposit laser energy into materials that otherwise exhibit minimal absorption at low laser intensities. During optical breakdown, a high density of free electrons is formed in the material, which dominates energy absorption, and, in turn, the material removal rate during ultrafast laser-material processing. Classical models assume spatially uniform electron population and constant laser intensity in the focal region, which results in a time-dependent expressions only, i.e., the rate equations, to predict electron evolution induced by nanosecond and picosecond pulses. For femtosecond pulses, however, the small spatial extent of the pulse requires that the pulse propagation be considered, which results in inhomogeneous plasma and localized electron formation during optical breakdown. In this work, a femtosecond breakdown model is combined with the classical rate equations to determine both time- and position-dependent electron density during femtosecond optical breakdown in water. The model exhibits good agreement when compared with experimental results. For other transparent or moderately absorbing dielectric media, the model also shows promise for determining the time- and position-dependent electron evolution induced by ultrashort laser pulses. Another interesting result is that the maximum electron density formed during femtosecond-laser-induced optical breakdown can exceed the conventional limit imposed by the plasma frequency.

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ENERGY TRANSMITTANCE AND SPATIAL PHASE IMPROVEMENT OF INTENSE ULTRASHORT LASER PULSES IN GAS-FILLED HOLLOW FIBER USING PRESSURE GRADIENT METHOD

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s021886350400189x ◽

2004 ◽

Vol 13 (02) ◽

pp. 291-299 ◽

Cited By ~ 1

Author(s):

MUHAMMAD NURHUDA ◽

HERU BUDIONO ◽

AKIRA SUDA ◽

KATSUMI MIDORIKAWA

Keyword(s):

Femtosecond Laser ◽

Pressure Gradient ◽

Hollow Fiber ◽

Gradient Method ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Ultrashort Laser Pulses ◽

Input Energy ◽

Spatial Phase ◽

Ultrashort Laser

A pressure gradient method for spectral broadening of intense-femtosecond laser pulses in gas-filled hollow fiber is proposed. The simulations using input energy of 6 mJ and pulse duration of 40 fs have shown that using the same value of ∫ p(x)dx, the energy transmittance can be enhanced by a factor of 25% compared to that of using constant gas pressure while the global spatial phase is also improved.

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