H. Baumhacker

Experiments with ASTERIX and ATLAS

We report on measurements of the equation-of-state of copper and gold in the multi-ten Megabar range, opacity measurements based on K-shell absorption in aluminium, and X-ray laser studies on a large number of neon-like ions applying the prepulse technique. For these investigations, the one-beam iodine laser facility ASTERIX emitting pulses with energies of up to 1000 J at 1315 nm and of up to 420 J at 438 nm was used. We also give a brief account of experimental and theoretical results referring to the propagation of an ultrashort pulse through underdense hydrogen or nitrogen plasmas and X-ray spectra from an optically field-ionized nitrogen plasma generated either by linearly or elliptically polarized light. For these investigations, 150-fs/200-mJ/800-nm pulses emitted from our titanium:sapphire laser ATLAS were employed.

Layout and performance of the Asterix IV iodine laser at Max-Planck-institut fuer Quantenoptik, Garching

The single beam Asterix IV high power iodine laser ((lambda) equals 1.32 micrometers ) provides at present a maximum output energy of 2.1 kJ at a pulse length of 5 ns and an output power of 4 TW at 0.3 ns pulses. This laser is designed to deliver pulses with lengths ranging from 0.2 to 5 ns with a maximum power of 5 TW and an energy of up to 2 kJ. Asterix IV has been developed on the 10 years experience with the 1 TW Asterix III laser and with the support of a 1D and a 3D pulse propagation code. Special emphasis has been put on achieving a high overall system efficiency and laser beam intensity profile as homogeneous as possible. In this paper the measures for optimizing the laser performance and the results obtained will be described.

Asterix IV iodine laser at MPQ Garching

The Asterix IV high power iodine laser is designed to deliver in a single beam output pulses with lengths ranges from 0.1 to 4 ns with a maximum power of 5 TW and an energy of up to 2 kJ. This laser has now achieved its projected output energy of 2.0 kJ and an output power of 4 TW. The Asterix laser has been developed on the basis of 10 years of experience with the 1 TW Asterix III laser and with the support of a 1D and a 3D pulse propagation code. Special emphasis has been put on obtaining an optimal overall efficiency of the laser system and a laser beam intensity profile as homogeneous as possible.

Laser−plasma research at MPQ

The ASTERIX iodine laser delivers after frequency tripling to λ = 0.44-μm laser pulses with energies up to 500 J at a pulse duration of 300 ps for target experiments. Experimental investigations of radiative transfer in low- and high-Z materials are reported.

Status report of the Asterix IV high-power iodine laser

The Asterix IV high power iodine laser was projected to deliver output pulse energies of up to 2 kJ at pulse lengths tp >= 1 ns in one beam. Using a mode-locked or a long-pulse oscillator the pulse duration can be adjusted in the range between 0.1 and 3 ns. In addition, in the fundamental wavelength at 1315 nm the laser can be operated at either the second or third harmonic at (lambda) equals 658 nm and (lambda) equals 438 nm, respectively. Up to now a maximum output energy of 1.3 kJ could be extracted which was -- at tp equals 0.4 ns -- limited only by the damage threshold of optical components. Emphasis has been put on improving the laser performance; e.g., the energy density of the top hat beam profile shows a modulation as small as +/- 6% and the output pulse energy can be kept stable within +/- 4% during a period of several months. Since 1988 the laser has been used for 3000 target shots and it has proved a reliable tool.