A 2.35-µm pumped subharmonic OPO reaches the spectral width of two octaves in the mid-IR

We used an orientation-patterned gallium phosphide (OP-GaP) crystal combined with an ultrafast 2.35-µm pump (1.2W, 79 MHz, 62 fs) to demonstrate a subharmonic sync-pumped OPO with an instantaneous output spectrum of 3–12.5 µm.