Output features of optical parametric chirped pulse amplification in LiB₃O₅ near 800  nm at different phase-matching...

We theoretically and experimentally investigated the output beam quality and wavefront distortion in four different phase-matching geometries in LBO-OPCPA at 800 nm: broadband noncollinear geometry, collinear geometry, pump-idler the Poynting vector collinear (S_p∥S_i) geometry, and pump-signal Poynting vector collinear (S_p∥S_s) geometry. It was found that the output profile is closely related to the noncollinear angle between Poynting vectors of parametric waves. However, the wavefront evolution depends mainly on the angles between the wave vectors. Broadband noncollinear geometry has the largest spatial modulation and wavefront distortion. Good output beam quality can be achieved in collinear geometry with little wavefront distortion, but the bandwidth is only approximately 10 nm. The S_p∥S_s and S_p∥S_i configurations result in a bandwidth of more than 20 nm with enhanced beam quality and small wavefront distortion. The two geometries have different output features wherein the former has a relatively lower modulation, and the latter shows smaller wavefront distortion.