Performance demonstration of the PEnELOPE main amplifier HEPA I using broadband nanosecond pulses

Abstract

We report on the energetic and beam quality performance of the second to the last main amplifier section HEPA I of the PEnELOPE laser project. A polarization coupled double-12-pass scheme to verify the full amplification capacity of the last two amplifiers HEPA I and II was used. The small signal gain for a narrow-band continuous wave laser was 900 and 527 for a broadband nanosecond pulse, demonstrating 12.6 J of output pulse energy. Those pulses, being spectrally wide enough to support equivalent 150 fs long ultrashort pulses, are shown with an excellent spatial beam quality. A first active correction of the wavefront using a deformable mirror resulted in a Strehl ratio of 76% in the single-12-pass configuration for HEPA I.

Petawatt and exawatt class lasers worldwide

“…It will be dedicated to the production of laser accelerated proton and ion beams with energies 100 MeV, relevant to future cancer treatments. The facility will deliver pulses of 150 J in 150 fs, giving 1 PW at 1 Hz centred at 1030 nm, with testing of one of the main amplifiers recently demonstrated [104] .…”

Millijoule ultrafast optical parametric amplification as replacement for high-gain regenerative amplifiers

“…For the system to be a real alternative for high-gain, one aspect of the design is to achieve similar output energies, which are often ranging from below 1 mJ, up to a few mJ for multistage, pre-amplification systems [16][17][18] . However, with respect to the replacement of regenerative amplifiers, parameters such as energy stability, beam quality and broadband gain are also relevant and should not be neglected.…”

A Yb:KGW dual-crystal regenerative amplifier

“…The Yb-ion has a long storage time, which is suitable for adopting a diode laser as a pump. Ytterbium-doped lasers have been developed to exhibit high pulse energy and power [13][14][15][16][17][18][19][20][21][22][23][24][25][26] .…”

“…The Petawatt Optical Laser Amplifier for Radiation Intensive Experiments (POLARIS) project based on the Yb:glass amplifier, which aimed to achieve a petawatt peak power output with a sub-hertz repetition rate, was started in 1999, and has demonstrated 54 J pulse energy [13][14][15] . Meanwhile, the Petawatt Energy Efficient Laser for Optical Plasma Experiments (PENELOPE) project with designed parameters of 150 J/150 fs/1 PW/1 Hz based on the Yb:CaF 2 crystal amplifier is under development [16] . Based on the Yb:YAG crystal, 1 J pulses with a pulse duration of 5 ps at 0.5 kHz were realized using a cryogenic Yb:YAG active mirror amplifier [17] .…”