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"Study of the Amplification of a XeCl laser: Multilevel model with bi-directional aspect of Amplified Spontaneous Emission (ASE)"
ABSTRACT
The amplification of powerful lasers corresponds to the higher energy need in the realization of modern applications such as microlitography in electronics, imprinting on precious stone in surface cleaning, microboring, ...etc.
In the prior study, my work focused on the amplification of a laser pulse by taking into account a simple model that is characterize by a two levels system of the excimer molecule XeCl and the one directional expansion of the amplified spontaneous emission ASE.
The present study entitled : "study of the amplification of an XeCl laser : multilevels model with bi-directional ASE" is a design of a more precise theoretical model taking into account the spectral complexity of the XeCl molecule (multilevel model) and the bi-directional propagation of the ASE.
These works took place in two stages :
- The first stage consist on a bibliographic study which bring us to the conception of the amplification technique, to obtain parameters values used in the numerical code and finally to write equations of evolution refer to the populations density and intensities of the different signals.
- The second phase is devoted to a fortran numerical programming and to a data processing by Excel program.
Results presented at the end of the work
- Oscillator laser pulse lose its shape during the amplification process (shortening and displacement of the peak).
- The energy density of the laser pulse increase to the saturation due to the degree of the amplification.
- The energy density of the ASE decrease to a lower limit as a function of the degree of the amplification.
- A more realistic model (i.e. with not much approximations) is necessary, with respect to the differences observe in the comparative study.
In future prospects, we will develop the laser cleaning process on different materials using high peak power, high energy per pulse excimer laser (Hercules), in order to determine for each of them the optimum working point and the significant process parameters.
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