QC594 : Stimulated Raman scattering by graphene plasmons
Thesis > Central Library of Shahrood University > Physics > MSc > 2023
Authors:
Nafiseh Bahrampour [Author], [Supervisor]
Abstarct: Abstract In this research, it is discussed the laser fundamental and then, its interaction with plasma and various instabilities. Then, it is explored the stimulated Raman scattering in the graphene substrate using high-power laser. Firstly, it is introduced the Fermi distribution function for electrons. Then, it is obtained the perturbed distribution function using the Vlasov equation and by integrating it, it is obtained the perturbed density and considering the Green's function method, the wave equation, perturbed density, these equations can be solved. It is obtained the electric field using appropriate boundary conditions and finally by using Snell's law and conservation of momentum, it is achieved a relationship that is similar to Brewster's angle in optics. In other words, considering the scattering angle equal to zero, it is obtained an incident angle, calling the Brewster's angle in plasma. In other words, in this system, although an intense laser pulse impinge to the graphene, no wave is excited even if its intensity of the laser puse is very high. According to the data and graphs presented in this research, it can be seen that by increasing the excited frequency, the scattering angle increases. In other words, when the frequency of the excited wave increases, this factor causes the scattering angle to become larger. By increasing the incident frequency of the wave , the amplitude of the excited wave initially increases, so that for , it reaches its maximum value and then the value of the excited wave decreases. In other words, there is an optimal state for for which the value of the excited wave has a maximum state. According to the changes of the dielectric permittivity, it is observed that by increasing the dielectric permittivity, the number of particles in this interaction increases and the energy is divided between the particles. As a result, a smaller contribution will reach the excited wave and its amplitude decreases.
Keywords:
#Keywords: Graphene #plasmon #stimulated Raman Scattering #Vlasov’s equation #Green method Keeping place: Central Library of Shahrood University
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