ABSTRACT
Abstract X-ray lasers pumped by picosecond laser pulses are bright, moderately uniform in beam profile and emit over an extremely narrow frequency range (v/Av~ 50000) for short durations (At ~ 2 - 3 ps). The high brightness is useful for applications as it can be used, for example, to 'outshine' a probed high temperature plasma so that the probing laser signal is much greater than the background plasma emission noise. The narrow frequency range of x-ray laser emission can be utilised depending on the application. In principle, high spectral resolution can be achieved with a low resolution detection instrument. The short duration of emission enables 'snap shots' of rapidly evolving events to be probed. A fundamental limit on the pulse duration At has recently become apparent as x-ray laser pulses are close to the Fourier transform limit with Av At ~ 1. These issues relevant to the application of short duration x-ray laser pulses will be explored. It is shown that the Fourier transform limit has not been reached yet and that x-ray laser pulses as short as 0.5 ps should be realisable.
