Nonlinear frequency down-conversion, particularly difference frequency generation (DFG) between near-infrared (NIR) pulses, is the predominant method for generating midinfrared (MIR) pulsed lasers in the $3-5\mu \mathrm{m}$ range via the idler wave. However, this approach suffers from inherently low conversion efficiency. The wavelength-dependent Manley-Rowe relations impose a fundamental limit on the maximum extractable power of the MIR idler from a given pump. Here, we propose a dual-DFG-OPA (optical parametric amplification) scheme that substantially enhances MIR idler conversion efficiency through synchronized parametric energy recycling. The signal wave, which carries the majority of the pump energy during DFG, is simultaneously reused as a secondary pump to drive optical parametric amplification of the MIR idler. Using a standard single-period periodically poled lithium niobate crystal, we theoretically demonstrate the dynamics and parametric gain control of this synchronized process based on a representative $3.6\mu \mathrm{m}$ DFG configuration pumped by 800 and 1030 nm pulsed lasers. Beyond improved pump energy utilization, the controlled, synchronous depletion of the signal wave mitigates the intrinsic back-conversion effect in parametric processes. Compared to conventional single-stage DFG, the dual-DFG-OPA architecture yields a twofold increase in output power of the $3.6\mu \mathrm{m}$ MIR idler wave.

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• Frequency conversion
• Laser-system design
• Nonlinear optical materials
• Optical parametric oscillators & amplifiers
• Second order nonlinear optical processes
• Ultrafast optics