Laser wakefield acceleration based x ray source using 225-TW and 13-fs laser pulses produced by thin film compression.

We show that 13-fs laser pulses associated with 225 TW of peak power can be used to produce laser wakefield acceleration (LWFA) and generate synchrotron radiation. To achieve this, 130-TW high-power laser pulses (3.2 J, 24 fs) are efficiently compressed down to 13 fs with the thin film compression (TFC) technique using large chirped mirrors after propagation and spectral broadening through a 1-mm-thick fused silica plate. We show that the compressed 13-fs laser pulse can be properly focused even if it induces a 10% degradation of the Strehl ratio. We demonstrate the usability of such a laser beam. We observe both an increase of the electron energy and of the betatron radiation critical energy when the pulse duration is reduced to 13 fs compared with the 24-fs case.