Time evolution and degradation of a supercontinuum in sapphire

Supercontinuum generation (SCG) in crystal is of great value in ultrafast and nonlinear optics. The stability of the long-term operation of SCG is crucial, and it requires a deeper understanding of the evolution of SCG over time. In this study, the evolution of SCG over time in sapphire under varying pump pulse energy was explored in detail, revealing its recoverability. Experimental results show that SC degradation and recovery are primarily affected by the accumulation of defects inside the material and the temperature fluctuations. By controlling the temperature of the sapphire, we succeeded in dramatically extending the stabilization duration of SCG under high-repetition-rate ultrashort laser pulses from a few minutes to several tens of minutes. This finding highlights the crucial role of temperature management in stabilizing SC and provides valuable insights for achieving longer and more stable SC output in future practical applications.