Abstract: Method for shielding a high-power laser apparatus (S) in which a laser beam is generated and then amplified in at least a first amplification stage, including spatial filtering (4) of the amplified laser beam, phase correction (3) carried out on the laser beam before it is spatially filtered, and a measurement of the aberrations (7) on the laser beam. The phase of the beam is corrected so as to produce a beam having minimal aberrations after spatial filtering. The shielding device (D, D?) implementing this method may in particular be employed in apparatus using an intense laser beam of high (terawatt) peak power and in proton therapy units.

Abstract: The present invention relates to a high-power femtosecond pulsed laser, the laser including: a source able to generate a train of input laser pulses having an envelope frequency and a carrier frequency; a chirped pulse amplification unit; and, a unit for controlling the phase drift between the envelope frequency and the carrier frequency of the output laser pulses. According to the invention, the unit for controlling the phase drift between the envelope frequency and the carrier frequency includes electro-optical phase-modulation unit that are placed on an optical path of the chirped pulse amplification unit in order to stabilize the phase drift between the envelope frequency and the carrier frequency of the output laser pulses as a function of time.

Abstract: A device for amplifying high-energy ultrashort light pulses, includes a generator (1), a first amplifying/time-stretching element (2) including a time-stretching element (3), a regenerative amplifier (4), a multipass amplifier (5) and a compressor (6). The device further includes a second amplifying/time-stretching element (11), arranged at the output of the generator (1), amplifying and time-stretching the initial light pulses (7) to generate amplified and time-stretched pulses (13), and a filtering element (12) arranged between the second amplifying/time-stretching element (11) and the amplification unit (2), blocking the low-amplitude light signals (14) of the amplified and time-stretched pulses (13).

Abstract: A high power solid-state non-regenerative optical amplification system (100) for amplifying a pulsed optical beam, includes a first optical amplification crystal (C1) and a second optical amplification crystal (C2) for amplifying the optical beam; optical pumping elements for longitudinal pumping amplification crystals (C1, C2); reflective optical elements (M?1, M?2, . . . , M?17) suitable for reflecting the optical beam so that the optical beam makes a total number of N sequential passes through the amplification crystals (C1, C2), wherein N is an integer and N>4. The reflective optical elements (M?1, M?2, . . . , M?17) are placed in a configuration suitable for alternatively interleaving the sequential optical beam passes through the 1st crystal (C1) and through the 2nd crystal (C2). A solid-state laser including the amplification system, and a method for amplifying a pulsed optical beam in a two-crystal multi-pass non-regenerative amplification system are also disclosed.