Demonstration of a collisionally excited optical-field-ionization xuv laser driven in a plasma waveguide

We describe the first demonstration of a collisionally excited optical-field-ionization laser driven within a waveguide. Lasing on the [Formula presented] transition at 41.8 nm in [Formula presented] was observed to be closely correlated to conditions under which the pump laser pulses were guided well by a gas-filled capillary discharge waveguide. Simulations of the propagation of the pump laser radiation show that gain was achieved over essentially the whole 30 mm length of the waveguide.