Programmable sub-pulse control and LSTM-PINN prediction in a mid-infrared SOPO

Programmable generation of mid-infrared pulse bursts with tailored sub-pulse features remains a critical challenge. Here, we demonstrate a 3.8 μm self-optical parametric oscillator based on an Nd:MgO:PPLN crystal, enabling independent control of sub-pulse number, spacing, and amplitude via dynamic stepwise Q-switching. At 10 kHz, the system achieves a typical sub-pulse energy of 77.3 μJ, a minimum pulse width of 23.5 ns, and a minimum interval of 150 ns. Beyond the hardware advance, we introduce a physics-informed LSTM-PINN framework that accurately predicts pulse width, amplitude, and energy, reaching R² = 0.99 and 0.93 on training and validation sets. This approach simplifies experimental trials and theoretical calculations, ensures reliable prediction of laser output characteristics, and lays the foundation for future intelligent control of lasers.