Advances in ultrafast kilowatt average power cryogenically cooled Yb:YAG lasers and applications at Colorado State University

Ultrafast pulses of Joule-level energy at kiloHertz repetition rate open new applications. We demonstrated a kW average power cryogenically-cooled Yb:YAG laser that generates picosecond pulses with record energy, >1 J, and efficient doubling of ns J pulses at 1 kHz. Laser filamentation and electrical discharge guiding in air was studied.