Comparative analysis of mid-infrared optical parametric amplification characteristics between Ba2Ga8GeS16 and CdSiP2

Mid-infrared sources are vital for spectroscopy, strong-field physics, and sensing. We compare B2GGS and CSP crystals in phase matching, group-velocity matching (GVM), and spatial walk-off under a unified dispersion model. Under [Formula: see text]m pumping, B2GGS provides a continuous GVM window over [Formula: see text]–10[Formula: see text][Formula: see text]m with noncollinear angles [Formula: see text]–9[Formula: see text], whereas CSP shows segmented GVM with a stronger wavelength dependence of [Formula: see text]. Notably, CSP can recover a continuous GVM window when pumped near [Formula: see text]m, covering [Formula: see text]–10[Formula: see text][Formula: see text]m. The two crystals show opposite wavelength-dependent walk-off trends due to refractive-index gradients. This provides guidance for crystal selection and mid-infrared optical parametric amplification optimization.