CQPMAmp · Chirped quasi-phasematching gratings for optical parametric chirped pulse amplification: physics, devices, and applications

Chirped (aperiodic) quasi-phasematched (CQPM) gratings offer many advantages in the context of optical parametric chirped pulse amplification (OPCPA), including ultrabroad bandwidths, engineerable gain spectra, and potential for high efficiency via adiabatic frequency conversion. Our main goals are to investigate CQPM devices and apply them to mid-infrared OPCPA systems. We will determine the limiting factors of our current high repetition rate mid-IR OPCPA system, develop an accurate numerical model, and design improved devices. As an example, with optimal nonlinear CQPM profiles, we plan to suppress spectral gain narrowing, and thereby obtain higher efficiencies and broader bandwidths.For future experiments, increases to the power and bandwidth of our existing system are required. We plan to develop an improved seed source based on a 1-micron-wavelength thin disk laser, spectrally broadened via supercontinuum generation (SCG). Concurrent upgrades to the pump laser to hundreds of Watts power are planned. To support these powers, we will explore approaches to scaling the CQPM devices to higher power.Recent developments in SESAM mode-locked thin disk lasers have enabled high-power, short-pulse operation (580 fs, 275 W, 17 microjoules). For some applications, much shorter pulse durations are needed. One way we plan to approach this problem is by performing SCG (seed generation) followed by OPA (for efficient conversion). Due to the short pump pulses, we will develop group-velocity matched CQPM OPCPA designs.With these laser sources, we plan to perform strong-field laser-matter experiments. For example, the high repetition rates and tunability will help us to explore the wavelength scaling of several processes related to high harmonic generation.