Laser-plasma accelerators as compact radiation sources

We explore ways of transforming laser radiation into incoherent and coherent electromagnetic radiation using laser-driven plasma waves. We present several examples based on the laser Wakefield accelerator (LWFA) and show that the electron beam and radiation from the it has several unique characteristics compared with conventional devices. We show that the energy spread can be much smaller than 1% at 130-150 MeV. Electron bunches of the order of 1 fs have been measured from the LWFA and it is predicted that pC charge, attosecond duration 100s MeV bunches are possible by suitably stimulating self-injection using a short density gradient. This makes LWFAs useful tools for scientists undertaking time resolved probing of matter. Furthermore, high charge relatively low energy (1-10 MeV) bunches with 10s – 100s nC charge and durations of 100s fs to ps, are also possible. These are useful for pulsed radiolysis, single shot imaging of macroscopic objects, and as a source of THz radiation. They also make excellent sources of gamma rays with high transverse coherence, which are useful as imaging tools. We present experimental evidence that ultra-short visible to XUV pulses (60 – 120 nm), as short as 20 fs, are produced directly from an undulator driven by a LWFA, due to the electron bunches having a duration of a few femto seconds, relative energy spreads less than 1 % and emittances of the order of 1 p mm mrad. With the reduction in size afforded by using LWFA driven radiation sources, and with the predicted advances in laser stability and repetition rate, ultra-short pulse radiation sources should become more affordable and widely used, which may change the way science is done