Control parameters for variation in frequency shift in laser induced breakdown of dielectrics
- Department of Physics, Lovely Professional University, Jalandhar, India.
- Associate Professor, Department of Physics, Lovely Professional University, Jalandhar, India.
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The main aim of this research work is to find the dependency of various laser-plasma parameters on frequency shift. When a Gaussian laser beam is incident on dielectric, the laser heats the seed electrons for a time scale too short for heat conduction and diffusion, and then the phase transition from solid to plasma state is spatially localized. Multi-photon absorption causes rapid electron hole pair production, which is enhanced further by tunneling ionization. As the electron density increases beyond threshold, time dependent refractive index decreases via nonlinear effects and ionization. Phase modulation of laser beam results into frequency broadening. The paper discusses the conditions for the optimization of frequency shift by varying different laser-plasma parameters. The model fits best to high intensities (1017 W/cm2) in paraxial ray approximation and WKB approximation.
[Supriya Rai and Niti Kant (2015); Control parameters for variation in frequency shift in laser induced breakdown of dielectrics Int. J. of Adv. Res. 3 (Oct). 458-462] (ISSN 2320-5407). www.journalijar.com
