Optimization of Optical Parametric Oscillator Performance Through Active Temporal Pulse Shaping

Achieving simultaneously high conversion efficiency and excellent beam quality remains a central challenge in high energy optical parametric oscillators (OPOs). Here, we demon strate that active temporal pulse shaping of the pump provides an effective and independent control parameter for optimizing OPO performance. A high-power master-oscillator power-amplifier laser system at 1064 nm is constructed to generate programmable Gaussian and top-hat nanosecond pulses through active pre compensation based on the inverse Frantz–Nodvik model. Both pulses preserve a near-diffraction-limited spatial quality (M22≈ 9), whereas top-hat pumping attains a comparable efficiency (∼ 35%) with a markedly improved beam quality (M2≈ 2.3). These results confirm that the temporal pulse shaping acts as an additional and independent degree of freedom—complementary to cavity design—for optimizing OPO performance. The demonstrated approach offers a straightforward and scalable method for other wavelength regimes and nonlinear systems.