Laser Generated Plasmas

The high power density available from focused Q-switched lasers makes it possible to create transient plasma clouds from almost all elements across the periodic table. While small in size, these plasma plumes emit intense electromagnetic radiation. Immediately after laser ignition, the plasmas reach extremely high temperatures and electron densities and then cool rapidly due to expansion and radiation. They evolve through different stages each characterized by specific emission spectra. Typically, emission is first dominated by strong plasma continuum radiation, followed by atomic ion emission lines, neutral atomic lines, and finally - if at all - by molecular fluorescence. We are exploring the "early" and "late" spectra induced by optical breakdown in atomic and molecular gases (Ar, N2 , O2 , H2 etc., and their mixtures). Because of the extreme conditions in these plasmas, we observe features relating to emission lines from unusually high excitation states of multiply charged atomic ions and molecular species as well as complex structures in the late stages of the decaying plasma (this link connects to an 640 kB AVI movie file; once loaded right-click and choose "play").
 

Recent publications:

 

Return to Molecular Photophysics Page.

Last updated by Lutz Hüwel - September 2005