Patent ID: 7782914

Claim:
A device for generating a high-energy particle pulse ( 20 ), comprising: a laser system ( 10 ) producing laser pulses ( 14 ) with pulse length shorter than 100 fs and capable to be focused to peak intensities greater than 10^18 W/cm 2; a target ( 16 ) capable of releasing a high-energy particle pulse ( 20 ) upon irradiation with at least one of said laser pulses ( 14 ); characterised by a device ( 12 ) for shaping a temporal intensity profile accompanying said at least one laser pulse ( 14 ) for increasing the laser contrast above 10^5, said laser contrast being the ratio of a peak intensity to a pedestal intensity of said one laser pulse ( 14 ), the pedestal intensity being a precursor intensity on a raising edge of said one laser pulse ( 14 ) or a successor intensity on a falling edge of said one laser pulse ( 14 ), the device ( 12 ) for shaping the temporal intensity profile comprising a non-linear Sagnac interferometer ( 54 ) having a pair of chirped mirrors ( 62 ) and apiece of n2-material ( 64 ), a non-linear polarisation rotation device, a saturated-absorption filter or a Pockels cell ( 80 ) optically switched by a part of said one laser pulse ( 14 ) impinging on a photoconductor ( 82 ) serving as a fast switch for the Pockels cell ( 80 ).