Nonlinear LiNbO₃ Local Electric Field Enhancement Photonic Crystal with Static Visible and Dynamic Asymmetric Laser Protection

The rapid development of high-energy laser technology imposes heightened requirements on multifunctional laser protection. In this article, we report a study of static visible and dynamic asymmetric laser protection window, utilizing a one-dimensional photonic crystal comprising LiNbO₃ and Nb₂O₅ defects fabricated by magnetron sputtering technique. The visible light transparency and asymmetric laser protection performance are attributed to photonic crystal energy band properties and significant local electric field enhancement. As 1064 nm laser energy levels are below 14.44 mJ/cm², the forward and backward incident transmittances are 75.63 and 77.68%, respectively. With an increase in laser energy to 91.62 mJ/cm², the forward and backward transmittances vary to 7.32 and 71.58% due to the combination of asymmetric electric field enhancement and the third-order nonlinear effect of LiNbO₃, achieving dynamic asymmetric laser protection. Notably, the sample exhibits a lower optical protection threshold of 46.08 mJ/cm² compared to that of traditional optical protection devices. Furthermore, the sample attains an average transmittance of 65.96% within the visible light band. This work presents inspirations for the preparation of multifunctional laser protection optical windows and advanced optical components.