Highly efficient double plasma mirror producing ultrahigh-contrast multi-petawatt laser pulses

Abstract

We present a highly efficient double plasma mirror (DPM) that provides ultrahigh-contrast multi-petawatt (PW) laser pulses with a temporal contrast ratio reaching 1 0 17 up to 160 ps and 1 0 12 up to 2 ps before the main pulse. The high reflectivity of 70%, along with the high-contrast enhancement factor of 700,000, was achieved from the DPM installed after the final stage of a 4 PW Ti:sapphire laser. The 4 PW laser was equipped with cross-polarized wave generation and optical parametric chirped-pulse amplification stages for initial high-contrast operation. The DPM operation was undertaken with conditions that did not modify the spatiotemporal profiles of incident multi-PW laser pulses. This highly efficient DPM with the high-contrast enhancement promises the utilization of multiple PMs as a practical rear end for upcoming tens of petawatt lasers to achieve ultrahigh temporal contrast.

Strong field physics pursued with petawatt lasers

“…A plasma mirror is utilized to enhance the contrast ratio after pulse compression, where weak prepulses pass through an anti-reflection window glass, while the main femtosecond pulse is reflected by the plasma generated by the leading edge of the main pulse. Choi et al reported that the contrast ratio of a multi-PW laser reached 10 −17 up to 160 ps and 10 −12 up to 2 ps before the main pulse by using a double plasma mirror system, which enabled irradiation of tens-ofnanometers-thick polymer targets at an intensity of about 10 22 W/cm 2 [45].…”

“…Since such a target can be easily destroyed by a prepulse arriving before the main ultra-high intensity pulse, the contrast ratio between a prepulse and the main pulse must be extremely high. A plasma mirror has been shown to enhance the contrast ratio by attenuating prepulses and amplified spontaneous emission existing with a main ultra-high intensity laser pulse; the double plasma mirror system developed at CoReLS has been shown to produce a contrast ratio of the laser pulse as low as 10 −17 up to 160 ps and 10 −12 up to 2 ps before the main pulse [45], which has enabled the use of polymer targets as thin as 5 nm.…”

Enhancement of pre-pulse and picosecond pedestal contrast of the petawatt J-KAREN-P laser

“…This pedestal, the rising slope just before the main pulse, has a non-negligible effect on the plasma physics processes occurring on the target surface. Because it is also difficult to remove these pre-pulses and pedestal, we plan to suppress them by installing a plasma mirror in the future [23].…”

“…Owing to the limitation of the available size and transverse parasitic oscillation in the Ti:sapphire gain media, femtosecond lasers based on optical parametric chirped-pulse amplifier (OPCPA) with a peak power of order 100 PW have been designed and are under construction [10,11]. The laser intensity will possibly exceed 10 23 W/cm 2 in the near future. With the development of ultra-high intensity femtosecond lasers, the investigations of electron acceleration, ion acceleration, x-/γ-ray generation, and astrophysical systems are being actively pursued.…”

“…saturable absorber [5], cross-polarized wave generation in nonlinear crystal [18], hybrid amplification in femtosecond lasers based on OPCPA at the front-end section [19], second harmonic generation (SHG) [20] and plasma mirrors (PM) [21]. The SHG and PM schemes are used as the final temporal cleaner at the full compressed pulse in the CPA laser chain [22,23]. ASE contrast of greater that 10 10 has been achieved by using these techniques at PW class peak powers.…”