Generation of high-contrast, 30 fs, 15 PW laser pulses from chirped-pulse amplification Ti:sapphire laser

TLDR

The system generates high‑contrast, 30‑fs, 1.5‑PW pulses at 0.1 Hz by CPA Ti:sapphire amplification, using index‑matching fluid and timing control to suppress parasitic lasing, a four‑grating compressor, a saturable absorber with Pockels cells to reduce ASE, and adaptive optics to achieve ~10^22 W cm^−2 focus. Record‑setting 1.5‑PW peak power was obtained with 44.5‑J, 30‑fs pulses—the highest output ever from a femtosecond CPA Ti:sapphire laser— after a booster amplifier pumped by four frequency‑doubled Nd:glass lasers delivered a maximum 60.2‑J energy at 120‑J pump.

Abstract

High-contrast, 30 fs, 1.5 PW laser pulses are generated from a chirped-pulse amplification (CPA) Ti:sapphire laser system at 0.1 Hz repetition rate. The maximum output energy of 60.2 J is obtained, at a pump energy of 120 J, from a booster amplifier that is pumped by four frenquency-doubled Nd:glass laser systems. During amplification, parasitic lasing is suppressed by index matching fluid with absorption dye and the careful manipulation of the time delay between the seed and pump pulses. An amplified pulse passes through a pulse compressor consisting of four gold-coated gratings. After compression, the measured pulse duration is 30 fs, and the output energy is 44.5 J, yielding a peak power of about 1.5 PW. The output energy of 44.5 J and output power of 1.5-PW are the highest values ever achieved from the femtosecond CPA Ti:sapphire laser system. To maintain a sufficiently high temporal contrast, a saturable absorber is installed in the front-end system with two ultrafast Pockels cells in order to minimize the amplified spontaneous emission (ASE) and pre-pulse intensity. An adaptive optics system is implemented for PW laser pulses and a focused intensity of about 1 × 10(22) W/cm(2) can be obtained when an f/3 optic is used.