VUV laser in the lyman band of molecular hydrogen pumped by fs titanium-sapphire laser pulses

We report lasing at 160 nm in the Lyman band of molecular hydrogen. The las er is pumped by 200 mJ/150 fs pulses from the ATLAS titanium-sapphire laser at our institute. The pump pulses are focused at an angle of incidence of 60 degrees onto a 9-cm-long gold target to a line focus, generating traveli ng-wave excitation. With 80 mbar of hydrogen in the target chamber we measu re an average gain of 1.1 cm(-1) and achieve a total gainlength product of 10. The evaluation of the far-field pattern shows that the beam originates from a region with an electron density of 5 x 10(15) cm(-3). A simple model of the H-2 laser is presented which explains the main part of our observat ions and supports a pump mechanism of photoelectron pumping.