Na-Hybridized LiNbO₃ Nanocrystal-Glass Composites for Ultra-Short Optical Pulse Detection

LiNbO₃ nanocrystal-glass composites (LiNbO₃-NGC), characterized by its unique 3D random domain structure, have shown great promise for significant applications, such as femtosecond pulse monitoring and full-color 3D displays. However, the nonlinear response of the LiNbO₃-NGC is greatly suppressed by the defects, and effective manipulation of these defects remains a long-standing challenge. In this study, a Na-hybridization strategy is proposed to control defects in the LiNbO₃-NGC to enhance its nonlinear properties and realizing its practical application for ultrashort optical pulse monitoring. The findings reveal that the incorporation of Na ions effectively reduces the defects within the composite, resulting in significantly improved nonlinear effects. By using this hybridized LiNbO₃-NGC, the transverse second-harmonic generation is achieved. An ultrashort optical pulse system is also constructed and successfully applied it for real-time quantitative measurement of the duration, distribution, and front tilting of optical pulses in the 10^-15 s scale. These results not only present an excellent example about defect engineering in nonlinear LiNbO₃-NGC but also point to practical applications for the measurement of extreme physical parameters.