Emerging Long-Wave Infrared Lasers

We report on progress in long-wave infrared (LWIR) laser development, represented by a 9-µm, 5-TW, 2-ps system employing electric-discharge, high-pressure, isotopic CO₂ amplifiers operating in chirped-pulse amplification mode at Brookhaven's Accelerator Test Facility. The system enables user experiments exploring relativistic laser–plasma interactions, advanced acceleration concepts, and novel radiation sources. Extending this platform to the femtosecond domain with peak powers in the tens of TW range is projected to unlock new regimes of LWIR laser–matter coupling. Planned upgrades include post-compression via nonlinear self-phase modulation in optical materials and a high-energy mid-IR OPA front-end for enhanced seed generation. Proof-of-principle tests and upcoming validation experiments are discussed. Target parameters correspond to few-cycle (≤300 fs) operation with normalized vector potentials a₀ = 10–30, scalable toward a₀ ≈ 100. Further advancement toward high-repetition-rate operation is envisioned through optical pumping of CO₂ high-pressure amplifiers using high-energy nanosecond mid-IR solid-state laser drivers or laser diodes