High-spatiotemporal-quality petawatt-class laser system

Abstract

We have developed a femtosecond high-intensity laser system that combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric CPA (OPCPA) techniques and produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front end in the system, for the compressed pulse without pumping the final amplifier, we found that the temporal contrast in this system exceeds 10(10) on the subnanosecond time scales, and is near 10(12) on the nanosecond time scale prior to the peak of the main femtosecond pulse. Using diffractive optical elements for beam homogenization of a 100 J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with a near-perfect top-hat-like intensity distribution.

Efficient multi-keV X-ray generation from high-contrast laser plasma interaction

“…Refer to Refs. [7,8] for further details for the pulse shape. To investigate the influence of the contrast ratio on the K , the contrast ratio of the leakage pulse was varied from 10 −7 to 10 −11 by controlling the operation conditions of the pulse cleaner and the optical shutters in the front-end stage of the system.…”

High power femtosecond lasers at ELI-NP

“…After first CPA system, fs pulses are intensity filtered and spectrally broadened by cross-polarized wave (XPW) generation in BaF2 crystals (figure 4). XPW is based on a degenerate four-wave mixing process (ω -ω + ω → ω) governed by the anisotropy, σ, of the third order nonlinearity tensor, χ (3) , of the BaF2 crystal. Perfect phase and group velocity matching of the two orthogonally polarized beams can be realized in the BaF2 which is a cubic crystal isotropic to linear optical properties.…”

“…Recently, PW-class Ti:sapphire have been demonstrated worldwide [2][3][4][5][6]. Till now, the highest peak intensity of 2 x 10 22 W/cm 2 was reported by focusing the 300 TW beam of a Ti:sapphire femtosecond laser using f/1 optics [7].…”

“…Gain narrowing and red-shifting during Ti:sapphire amplification contribute to the increase of the amplified re-compressed pulse [11]. In order to preserve a broad amplification bandwidth, special techniques are used in the chirped pulse amplification chains, like optical parametric chirped pulse amplification -OPCPA [3], cross-polarized wave generation -XPW [12], and spectrum management using spectral filters [11]. Flat spectral phase over a large bandwidth can be obtained by the correction of high-order phase distortions using acousto-optic programmable dispersion filters (AOPDFs) [13,14].…”

Contrast Improvement of Relativistic Few-Cycle Light Pulses

“…-saturable absorber Itatani et al (1998); Kiriyama et al (2010), is applied after some preamplifier stages at the µJ energy level in compressed pulses with ∼ 20% efficiency. The contrast is bettered by only 2 OOM.…”