Femtosecond Laser Deposition of Diamond-Like Carbon Films

1995 ◽  
Vol 397 ◽  
Author(s):  
F. Qian ◽  
R. K. Singh ◽  
S. Dutta ◽  
P.P. Pronko ◽  
W.H. Weber
Keyword(s):  
Kinetic Energy ◽  
Femtosecond Laser ◽  
Film Surface ◽  
Laser Pulses ◽  
High Energy ◽  
Carbon Films ◽  
Femtosecond Laser Pulses ◽  
Diamond Like Carbon ◽  
Carbon Ions ◽  
Raman Spectrometry

ABSTRACTWe have deposited unhydrogenated diamond-like carbon (DLC) films with 100 femtosecond laser pulses, at intensities in the 3x1014 - 6.5x1015 W/cm2 range. Film surface topography, optical property, and bonding structure were examined, respectively, with atomic force microscopy (AFM), spectroscopie ellipsometry (SE) and Raman spectrometry. The femtosecond pulse generated plasma was studied through time-of-flight (TOF) experiment. The most probable kinetic energy of carbon ions was estimated to be in the 300 – 2000 eV range, increasing with laser intensity. In addition, a unique ‘suprathermal’ component with kinetic energy ranging from 4 to 40 keV was observed in the TOF spectrum. This high energy peak is believed to originate from fast ions in a solid density plasma created during the absorption of each femtosecond laser pulse.

Diamond-like carbon films deposited by femtosecond laser pulses

2007 ◽  
Author(s):  
Yanlong Guo ◽  
Xiao Yuan ◽  
Shuyun Wang ◽  
Changyong Lu ◽  
Xiaobing Wang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Carbon Films ◽  
Femtosecond Laser Pulses ◽  
Diamond Like Carbon

Wavelength tunable, high energy femtosecond laser pulses directly generated from large-mode-area photonic crystal fiber

2012 ◽  
Vol 285 (10-11) ◽  
pp. 2715-2718 ◽  
Author(s):  
Chi Zhang ◽  
Yu-ying Zhang ◽  
Ming-lie Hu ◽  
Si-jia Wang ◽  
You-jian Song ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Photonic Crystal Fiber ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Large Mode Area ◽  
Crystal Fiber ◽  
Wavelength Tunable ◽  
Mode Area

Fabrication of Anisotropic Structures on the Surface of Amorphous Silicon by Femtosecond Laser Pulses

2020 ◽  
Vol 312 ◽  
pp. 192-199
Author(s):  
Dmitrii V. Shuleiko ◽  
Mikhail N. Martyshov ◽  
Danila V. Orlov ◽  
Denis E. Presnov ◽  
Stanislav V. Zabotnov ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Femtosecond Laser ◽  
Volume Fraction ◽  
Film Surface ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Surface Structures ◽  
Radiation Polarization ◽  
Direction Parallel ◽  
Nanocrystalline Si

Anisotropic periodic relief in form of ripples was formed on surface of amorphous hydrogenated silicon (a-Si:H) films by femtosecond laser pulses with the wavelength of 1.25 μm. The orientation of the surface structures relative to laser radiation polarization vector depended on the number of laser pulses N acting on the film surface. When N = 30, the structures with 0.88 μm period were formed orthogonal to the laser radiation polarization; at N = 750 the surface structures had period of 1.12 μm and direction parallel to the polarization. The conductivity of the laser-modified a-Si:H films increased by 3 to 4 orders of magnitude, up to 3.8·10–5 (Ω∙cm)–1, due to formation of nanocrystalline Si phase with a volume fraction from 17 to 30%. Anisotropy of the dark conductivity, as well as anisotropy of the photoconductivity spectral dependences was observed in the modified films due to depolarizing influence of periodic microscale relief and uneven distribution of nanocrystalline Si phase within such laser-induced structure.

scholarly journals Femtosecond Laser Pulses Amplification in Crystals

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 347
Author(s):  
Dabu
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Phase Matching ◽  
Chirped Pulse ◽  
Nonlinear Crystals ◽  
Pulse Amplification ◽  
Chirped Pulse Amplification ◽  
Laser Crystals

This paper describes techniques for high-energy laser pulse amplification in multi-PW femtosecond laser pulses. Femtosecond laser pulses can be generated and amplified in laser media with a broad emission spectral bandwidth, like Ti:sapphire crystals. By chirped pulse amplification (CPA) techniques, hundred-Joule amplified laser pulses can be obtained. Multi-PW peak-power femtosecond pulses are generated after recompression of amplified chirped laser pulses. The characteristics and problems of large bandwidth laser pulses amplification in Ti:sapphire crystals are discussed. An alternative technique, based on optical parametric chirped pulse amplification (OPCPA) in nonlinear crystals, is presented. Phase-matching conditions for broad bandwidth parametric amplification in nonlinear crystals are inferred. Ultra-broad phase matching bandwidth of more than 100 nm, able to support the amplification of sub-10 fs laser pulses, are demonstrated in nonlinear crystals, such as Beta Barium Borate (BBO), Potassium Dideuterium Phosphate (DKDP), and Lithium Triborate (LBO). The advantages and drawbacks of CPA amplification in laser crystals and OPCPA in nonlinear crystals are discussed. A hybrid amplification method, which combines low-medium energy OPCPA in nonlinear crystals with high energy CPA in large aperture laser crystals, is described. This technique is currently used for the development of 10-PW laser systems, with sub-20 fs pulse duration and more than 1012 intensity contrast of output femtosecond pulses.

scholarly journals Towards optimization of femtosecond laser pulse nanostructuring of targets for high-intensity laser experiments in vacuum

2021 ◽  
Vol 127 (7) ◽  
Author(s):  
A. Andreev ◽  
J. Imgrunt ◽  
V. Braun ◽  
I. Dittmar ◽  
U. Teubner
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
High Intensity ◽  
Extreme Ultraviolet ◽  
Theoretical Models ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Laser Development ◽  
Laser Experiments

AbstractThe interaction of intense femtosecond laser pulses with solid targets is a topic that has attracted a large amount of interest in science and applications. For many of the related experiments a large energy deposition or absorption as well as an efficient coupling to extreme ultraviolet (XUV), X-ray photon generation, and/or high energy particles is important. Here, much progress has been made in laser development and in experimental schemes, etc. However, regarding the improvement of the target itself, namely its geometry and surface, only limited improvements have been reported. The present paper investigates the formation of laser-induced periodic surface structures (LIPSS or ripples) on polished thick copper targets by femtosecond Ti:sapphire laser pulses. In particular, the dependence of the ripple period and ripple height has been investigated for different fluences and as a function of the number of laser shots on the same surface position. The experimental results and the formation of ripple mechanisms on metal surfaces in vacuum by femtosecond laser pulses have been analysed and the parameters of the experimentally observed “gratings” interpreted on base of theoretical models. The results have been specifically related to improve high-intensity femtosecond-laser matter interaction experiments with the goal of an enhanced particle emission (photons and high energy electrons and protons, respectively). In those experiments the presently investigated nanostructures could be generated easily in situ by multiple pre-pulses irradiated prior to a subsequent much more intense main laser pulse.

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