Burst-mode pumping scheme for longwave parametric amplification

High-peak-power longwave OPAs operating above the wavelength of 5μm [1] require high-energy picosecond pump pulses >2 μm. These can be generated directly in laser amplifiers, e.g. Ho-doped [1, 2] or via cascaded OPAs [3]. Burst-mode pump lasers offer great advantages over single-pulse amplifiers because they help overcoming the challenges of chirped-pulse as well as direct picosecond pulse amplifiers operating in the singlepulse amplification mode. The techniques of coherent pulse combining [4] and coherent pulse stacking of pulse bursts [5] offer an opportunity, at the expense of interferometric phase stabilization, for a multifold energy increase in a single pulse without modifying the laser amplifier itself. Simple non-interferometric combining techniques, such as energy combination via frequency doubling in a non-collinearly phase-matched nonlinear crystal also exist, but they are not suitable for pumping LWIR OPAs.