Tunable 3.75-4.35  µm optical parametric generation using cascaded non-critical phase matching in CdSiP₂

We demonstrate a cascaded optical parametric generation architecture based on type-I non-critical phase matching (NCPM) in CdSiP₂ producing tunable mid-wave infrared radiation in the first atmospheric transmission window. The architecture was implemented with two Nd:YAG pump lasers: a 10 Hz flashlamp-pumped system and a 1 kHz diode-pumped Nd:YAG system, generating up to 108 and 17 µJ at 3.75 µm, respectively. Temperature tuning of the second NCPM CdSiP₂ stage, with orthogonal crystal c axes to the first stage, enabled continuous wavelength tuning from 3.75 to 4.35 µm.