Cryocooled Ti:sapphire amplifiers for laser plasma acceleration at high repetition rates

The performance of Laser Plasma Accelerators (LPAs) is constrained by the low repetition rates of today’s flashlamp-pumped Ti:Sapphire lasers, mainly limited by heat management challenges. To address these challenges, cryocooled amplifiers are being developed, enhancing thermal conductivity and reducing thermal lens effects to improve energy and pointing stability. KALDERA, a Joule-class Ti:Sapphire laser operating in the kHz regime is under development at DESY, featuring a cryocooled amplifier chain. The preamplifier produces 40 mJ pulses at 1 kHz with a Gaussian beam profile, while the main amplifier delivers 700 mJ pulses at 100 Hz with sub-30 fs pulses post-compression and a near top-hat beam profile. Active and passive stabilization measures have been implemented to optimize performance. These advances aim to enable higher repetition rates and more stable operation, critical for generating and driving plasma waves effectively.