  When an ArF excimer laser beam was focused in a high pressure argon gas from
50 to 130 atm, the plasma development is observed by streak camera from side
window of chamber. The high pressure ArF laser plasma develops symmetrically
and the plasma produced by ArF excimer laser hardly develops as compared with
the plasma produced by XeCl. The photon energy of ArF laser light is higher
than the XeCl laser. The transmittance of ArF laser light was measured. Almost
all the laser light is transmitted as the frequency of laser light is higher
than the plasma frequency, and the energy of laser light is hardly working for
plasma development. The backward and forward plasma development produced by the
ArF laser was calculated by the breakdown wave and the radiation supported
shock wave, which agreed with the experimental one. The backward development
mechanism of high pressure ArF plasma is same as one of plasma produced by XeCl
laser. However, the forward development mechanism of ArF plasma differs from
one of plasma produced by XeCl laser.
