Optical parametric oscillator pumped at ~1 µm with intracavity mid-IR difference-frequency generation in OPGaAsWe report with a femtosecond optical parametric oscillator (OPO) for the deep-infrared (deep-IR) determined by the Kerr-lens-mode-locked Ti:sapphire laser given that the pump supply. By deploying a novel cascaded intracavity arrangement,