Optical breakdown thresholds in helium

1967 ◽  
Vol 3 (6) ◽  
pp. 264 ◽  
Author(s):  
J.W. Gardner
Keyword(s):  
Optical Breakdown

scholarly journals Femtosecond-Laser Assisted Surgery of the Eye: Overview and Impact of the Low-Energy Concept

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 122
Author(s):  
Catharina Latz ◽  
Thomas Asshauer ◽  
Christian Rathjen ◽  
Alireza Mirshahi
Keyword(s):  
Surgical Techniques ◽  
Numerical Aperture ◽  
Optical Breakdown ◽  
Pulse Frequency ◽  
Low Energy ◽  
Human Cornea ◽  
Energy Concept ◽  
High Pulse Frequency ◽  
Fs Laser ◽  
High Pulse

This article provides an overview of both established and innovative applications of femtosecond (fs)-laser-assisted surgical techniques in ophthalmology. Fs-laser technology is unique because it allows cutting tissue at very high precision inside the eye. Fs lasers are mainly used for surgery of the human cornea and lens. New areas of application in ophthalmology are on the horizon. The latest improvement is the high pulse frequency, low-energy concept; by enlarging the numerical aperture of the focusing optics, the pulse energy threshold for optical breakdown decreases, and cutting with practically no side effects is enabled.

Surface Laser Plasma in Laser Treatment of Materials in High Pressure Gases

1991 ◽  
Vol 236 ◽  
Author(s):  
A. Smirnov ◽  
C. Dupuy ◽  
G. Flamant
Keyword(s):  
High Pressure ◽  
Laser Treatment ◽  
Laser Plasma ◽  
Holographic Interferometry ◽  
Aerosol Particles ◽  
Optical Breakdown ◽  
Plasma Generation ◽  
Additional Information ◽  
Surface Laser ◽  
Condensation Front

AbstractUsing holographic interferometry the surface laser plasma generation in high pressure gases has been investigated. Additional information about the generation of surface cover laser plasma, optical breakdown in the presence of aerosol particles and condensation front forming in high pressure gases is given.

scholarly journals Reflecting petawatt lasers off relativistic plasma mirrors: a realistic path to the Schwinger limit

2021 ◽  
Vol 9 ◽  
Author(s):  
Fabien Quéré ◽  
Henri Vincenti
Keyword(s):  
Light Intensity ◽  
High Power ◽  
Quantum Electrodynamics ◽  
Laser Light ◽  
Optical Breakdown ◽  
Relativistic Plasma ◽  
Laser Beams ◽  
Relativistic Motion ◽  
Quantum Vacuum ◽  
High Power Lasers

Abstract The quantum vacuum plays a central role in physics. Quantum electrodynamics (QED) predicts that the properties of the fermionic quantum vacuum can be probed by extremely large electromagnetic fields. The typical field amplitudes required correspond to the onset of the ‘optical breakdown’ of this vacuum, expected at light intensities >4.7×1029 W/cm2. Approaching this ‘Schwinger limit’ would enable testing of major but still unverified predictions of QED. Yet, the Schwinger limit is seven orders of magnitude above the present record in light intensity achieved by high-power lasers. To close this considerable gap, a promising paradigm consists of reflecting these laser beams off a mirror in relativistic motion, to induce a Doppler effect that compresses the light pulse in time down to the attosecond range and converts it to shorter wavelengths, which can then be focused much more tightly than the initial laser light. However, this faces a major experimental hurdle: how to generate such relativistic mirrors? In this article, we explain how this challenge could nowadays be tackled by using so-called ‘relativistic plasma mirrors’. We argue that approaching the Schwinger limit in the coming years by applying this scheme to the latest generation of petawatt-class lasers is a challenging but realistic objective.

Laser ablation of YBCO targets and optical-breakdown-assisted PLD for high T c superconducting thin films deposition

1998 ◽  
Author(s):  
Ileana Apostol ◽  
Razvan Stoian ◽  
C. Luculescu ◽  
Razvan V. Dabu ◽  
Aurel Stratan ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Optical Breakdown ◽  
Superconducting Thin Films

Optical breakdown in gases of medium ionization potential

1971 ◽  
Vol 7 (5) ◽  
pp. 204-205 ◽  
Author(s):  
W. Holzer ◽  
P. Ranson ◽  
P. Peretti
Keyword(s):  
Ionization Potential ◽  
Optical Breakdown

Early Dynamics of a Laser-induced Underwater Shock Wave

2021 ◽  
Author(s):  
Guihua Lai ◽  
Siyuan Geng ◽  
Hanwen Zheng ◽  
Zhifeng Yao ◽  
Qiang Zhong ◽  
...  
Keyword(s):  
Shock Wave ◽  
Numerical Method ◽  
Cavitation Bubble ◽  
Laser Energy ◽  
Optical Breakdown ◽  
Pulsed Laser ◽  
Underwater Shock Wave ◽  
Time Resolved ◽  
High Attenuation ◽  
Nanosecond Pulsed Laser

Abstract The objective of this paper is to observe and investigate the early evolution of the shock wave, induced by a nanosecond pulsed laser in still water. A numerical method is performed to calculate the propagation of the shock wave within 1µs, after optical breakdown, based on the Gilmore model and the Kirkwood-Bethe hypothesis. The input parameters of the numerical method include the laser pulse duration, the size of the plasma and the maximally extended cavitation bubble, which are measured utilizing a high time-resolved shadowgraph system. The calculation results are verified by shock wave observation experiments at the cavitation bubble expansion stage. The relative errors of the radiuses and the velocity of the shock wave front, reach the maximum value of 45% at 5 ns after breakdown and decrease to less than 20% within 20 ns. The high attenuation characteristics of the shock wave after the optical breakdown, are predicted by the numerical method. The quick time and space evolution of the shock wave are carefully analyzed. The normalized shock wave width is found to be independent of the laser energy and duration, and the energy partitions ratio is around 2.0 using the nanosecond pulsed laser.

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