CO2 laser induced gas breakdown in preionized argon

1980 ◽  
Vol 58 (2) ◽  
pp. 153-163
Author(s):  
J. Santiago ◽  
A. M. Robinson
Keyword(s):  
Co2 Laser ◽  
Electric Discharge ◽  
Laser Pulses ◽  
Cascade Model ◽  
Focal Region ◽  
Model Yield ◽  
Laser Induced Breakdown ◽  
Uv Photons ◽  
Gas Breakdown ◽  
Good Agreement

CO2 laser induced breakdown of argon is investigated as a function of pressure and preionization. The gas is preionized by uv photons from an electric discharge. By varying the time between the discharge and laser pulses, initial densities in the focal region vary from 109 cm−3 to 1012 cm−3. Numerical calculations of the breakdown process based on a cascade model yield thresholds which are in good agreement with measurements.

Simulation and Measurement of the Laser Induced Breakdown in Air and Argon for Nanosecond Order Pulses

2012 ◽  
Author(s):  
Yongjun Choi ◽  
Chuandong Zhou ◽  
Peter Stoltz ◽  
Sachin Joshi ◽  
Azer Yalin
Keyword(s):  
Impact Ionization ◽  
Focal Spot ◽  
Laser Energy ◽  
Fluid Dynamic ◽  
Ambient Pressure ◽  
Laser Pulses ◽  
Focal Region ◽  
Laser Propagation ◽  
Laser Induced Breakdown ◽  
Photon Ionization

The interest in lasers for engine ignition is the possibility of higher efficiency and reduction of pollutants compared with conventional spark plugs. The interest in this area is to understand the laser energy needed for breakdown and ignition in order to better design practical systems. To support such development, the laser induced breakdown of air is simulated by the use of a two-dimensional computational fluid-dynamic model for 10 and 46 ns laser pulses for several pressures and focal spot sizes. The simulation includes the laser propagation, multi-photon ionization, impact ionization, electrons heating and energy loss. The dependence of breakdown irradiance on pulse duration, ambient pressure, and dimensions of the focal region is investigated and compared with experimental results.

scholarly journals Laser-induced breakdown spectroscopy of trisilane using infrared CO2 laser pulses

2007 ◽  
Vol 102 (10) ◽  
pp. 103302 ◽  
Author(s):  
J. J. Camacho ◽  
J. M. L. Poyato ◽  
L. Díaz ◽  
M. Santos
Keyword(s):  
Co2 Laser ◽  
Laser Pulses ◽  
Laser Induced Breakdown Spectroscopy ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

scholarly journals Laser-sound: optoacoustic transduction from digital audio streams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Konstantinos Kaleris ◽  
Björn Stelzner ◽  
Panagiotis Hatziantoniou ◽  
Dimosthenis Trimis ◽  
John Mourjopoulos
Keyword(s):  
Computational Model ◽  
Spatial Location ◽  
Laser Pulses ◽  
Prototype System ◽  
Digital Audio ◽  
Laser Induced Breakdown ◽  
Pulse Streams ◽  
Audio Streams ◽  
Sound Transduction ◽  
Good Agreement

AbstractThis work presents a novel laser-based optoacoustic transducer capable of reproducing controlled and continuous sound of arbitrary complexity in the air or on solid targets. Light-to-sound transduction is achieved via laser-induced breakdown, leading to the formation of plasma acoustic sources in any desired spatial location. The acoustic signal is encoded into pulse streams via a discrete-time audio modulation and is reproduced by fast consecutive excitation of the target medium with appropriately modulated laser pulses. This results in the signal being directly reconstructed at the desired location of the target medium without the need for a receiver or demodulation device. In this work, the principles and evaluation results of such a novel laser-sound prototype system are presented. The performance of the prototype is evaluated by systematic experimental measurements of audio test signals, from which the basic acoustical response is derived. Moreover, a generic computational model is presented that allows for the simulation of laser-sound reproduction of 1-bit or multibit audio streams. The model evaluations are validated by comparison with the acoustic measurements, whereby a good agreement is found. Finally, the computational model is used to simulate an ideal optoacoustic transducer based on the specifications of state-of-the-art commercially available lasers.

Emission of molecular nitrogen at tight focusing of femtosecond laser pulses in air

2021 ◽  
pp. 42-48
Author(s):  
A.A. Ilyin ◽  
◽  
K.A. Shmirko ◽  
S.S. Golik ◽  
D.Yu. Proschenko ◽  
...  
Keyword(s):  
Particle Density ◽  
Molecular Nitrogen ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Plasma Particle ◽  
Sharp Drop ◽  
Radiation Level ◽  
Femtosecond Radiation ◽  
Tight Focusing ◽  
Good Agreement

A numerical model describing the dynamics of plasma particle density upon filamentation of femtosecond radiation in the air is presented. The simulation results are in good agreement with the experimental data. The pumping processes of the N2 and N2+ radiative levels are investigated. The model predicts a sharp drop in electron temperature and density within 1 ns. For the first positive nitrogen system, an excess of the population of the upper radiation level over the population of the lower one is observed for 550 ps.

Sign in / Sign up

Export Citation Format

Share Document