Laser and Particle Beams



A review of X-ray laser development at Rutherford Appleton Laboratory


G.J.  TALLENTS  a1 c1, Y.  ABOU-ALI  a1, M.  EDWARDS  a1, R.  KING  a1, G.J.  PERT  a1, S.J.  PESTEHE  a1, F.  STRATI  a1, C.L.S.  LEWIS  a2, R.  KEENAN  a2, S.  TOPPING  a2, A.  KLISNICK  a3, O.  GUILBAUD  a3, D.  ROS  a3, R.  CLARKE  a4, M.  NOTLEY  a4 and D.  NEELY  a4
a1 Department of Physics, University of York, York YO10 5DD, UK
a2 School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK
a3 Laboratoire de Spectroscopie Atomique et Ionique, Universite Paris-Sud, 91405 Orsay, France
a4 Central Laser Facility, Rutherford Appleton Laboratory, Chilton OX11 OQX, UK

Abstract

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.

Correspondence:
c1 Address correspondence and reprint requests to: G.J. Tallents, Department of Physics, University of York, York YO10 5DD, United Kingdom. E-mail: gjt5@york.ac.uk