Numerical study of nanosecond laser interactions with micro-sizedsingle droplets and sprays of xenon

• Published in: Journal of applied physics 2007-02, Vol.101 (4), p.043302-043302-13
• Main Authors: Auguste, T., de Gaufridy de Dortan, F., Ceccotti, T., Hergott, J. F., Sublemontier, O., Descamps, D., Schmidt, M.
• Format: Article
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2432870

We present a thorough numerical study on interactions of a nanosecond laser with micro-sized xenon droplets. We developed a code which allows simulation of laser interactions with a single droplet as well as a spray. We give a detailed description of the code, and we present results on the dynamics of a microplasma produced by irradiation of a single xenon droplet with a laser focused at peak vacuum intensity in the 5 × 10 10 − 5 × 10 12 W ∕ cm 2 range. We find that the heating of the plasma depends dramatically on the laser parameters (duration, pulse shape, and intensity) on one hand, and on the droplet diameter on the other. We also present results obtained with a spray which show that the dynamics of the microplasmas is very sensitive to the position of the droplets in the interaction volume. The predictions of our model agree well with recent experimental observations performed on laser-produced plasma sources for extreme ultraviolet lithography. In particular, the postprocessing of our data with a sophisticated atomic physics code has allowed us to reproduce quite well the spectrum emitted in the extreme ultraviolet range by a xenon plasma generated by laser irradiation of a spray of droplets.