A review of X-ray laser development at Rutherford Appleton Laboratory
Recent experiments undertaken at the Rutherford Appleton Laboratory to produce X-ray lasing over the 5–30 nm wavelength range are reviewed. The efficiency of lasing is optimized when the main pumping pulse interacts with a preformed plasma. Experiments using double 75-ps pulses and picosecond pulses superimposed on 300-ps background pulses are described. The use of travelling wave pumping with the approximately picosecond pulse experiments is necessary as the gain duration becomes comparable to the time for the X-ray laser pulse to propagate along the target length. Results from a model taking account of laser saturation and deviations from the speed of light c of the travelling wave and X-ray laser group velocity are presented. We show that X-ray laser pulses as short as 2–3 ps can be produced with optical pumping pulses of [approximate]1-ps.(Received November 15 2001)
(Accepted November 20 2001)
Key Words: Laser; Plasma; Saturation; X-ray.
c1 Address correspondence and reprint requests to: G.J. Tallents, Department of Physics, University of York, York YO10 5DD, United Kingdom. E-mail: email@example.com