The co-operation between the High Intensity Laser laboratory (HILL) at
the Department of Experimental Physics of the University of Szeged (DEP USZ)
and the High Power Excimer Laser Laboratory at the China Institute of Atomic
Energy (CIAE) has more than six years of successful history. The basis of
the cooperation originally was the investigation, development and plasma-physics
application of excimer laser systems in the femtosecond pulse range. In the frame
of this cooperation scientific visits, exchange of information and joint
research and development activity have been realized.
Since 2004 the collaboration strengthened in the frame of the Hungarian Chinese
Intergovernmental S&C Cooperation Programme. The first contract was obtained
for one year in 2004, which has been followed by the next contract for 2005-2006.
This Programme gave the possibility to extend the cooperation to the research and
application of nanosecond laser systems as well, moreover the number of the
scientific visits increased each year.
In the frame of this Cooperation Programme an excimer laser amplifier of high
beam uniformity was developed. This is a special 3-channel laser amplifier capable
of generating or amplifying 3 identical pulses, each having >300 mJ energy.
The 20 ns long pulses are temporally separated by 20 ns, thus they give a
possibility to efficiently use the >60 ns pumping time of the e-beam pumped
preamplifier at CIAE. Now this amplifier is integrated into the existing system
and operates as the front end of the HEAVEN-I laser system. Different methods
for the characterization and for the improvement of the beam homogeneity were
considered and studied. As a result a beam uniformity of ~2% was achieved
at the CIAE.
Laser-matter interactions are studied with similar laser intensities in
both laboratories. While in Hungary short-pulse intensities in the order
of about 1018 W/cm2 are achieved in a 1 µm diameter focal spot
(necessitating relatively low laser energy), in China similar intensities
are produced by a much larger laser power in a larger spot area. It is known
that in target experiments the investigated process can only be considered
as one dimensional, when the focal spot diameter is significantly larger
than the layer thickness. On the other hand smaller dimensions provide easier
way for diagnostic developments. The experience accumulated in x-ray
spectroscopy and shock-wave studies in Hungary can be of interest to carry out
joint EOS study experiments with the ns laser pulses. These facts give
possibilities for alternate and complementary studies.
At present CIAE plays the most important role in excimer laser
research in China and is the host institute in the National High-Tech
Project recently launched in China.