Anthur Aravind P, Zhang Haizhong, Paniagua-Dominguez Ramon, Kalashnikov Dmitry A, Ha Son Tung, Maß Tobias W W, Kuznetsov Arseniy I, Krivitsky Leonid
A*STAR (Agency for Science, Technology and Research) Research Entities, Institute of Materials Research and Engineering, 2 Fusionopolis Way, # 08-03 Innovis, Singapore 138634, Singapore.
Nano Lett. 2020 Dec 9;20(12):8745-8751. doi: 10.1021/acs.nanolett.0c03601. Epub 2020 Nov 18.
Resonant metasurfaces are an attractive platform for enhancing the nonlinear optical processes, such as second harmonic generation (SHG), since they can generate large local electromagnetic fields while relaxing the phase-matching requirements. Here, we demonstrate visible range, continuous wave (CW) SHG by combining the attractive material properties of gallium phosphide with high quality-factor photonic modes enabled by bound states in the continuum. We obtain efficiencies around 5e-5% W when the system is pumped at 1200 nm wavelength with CW intensities of 1 kW/cm. Moreover, we measure external efficiencies of 0.1% W with pump intensities of only 10 MW/cm for pulsed irradiation. This efficiency is higher than the values previously reported for dielectric metasurfaces, but achieved here with pump intensities that are two orders of magnitude lower. These results take metasurface-based SHG a step closer to practical applications.
共振超表面是增强诸如二次谐波产生（SHG）等非线性光学过程的一个有吸引力的平台，因为它们可以在放宽相位匹配要求的同时产生大的局部电磁场。在此，我们通过将磷化镓具有吸引力的材料特性与由连续统中的束缚态实现的高品质因子光子模式相结合，展示了可见光范围内的连续波（CW）二次谐波产生。当系统在1200nm波长处以1kW/cm的连续波强度泵浦时，我们获得了约5e-5%W的效率。此外，对于脉冲辐照，在仅10MW/cm的泵浦强度下，我们测量到的外部效率为0.1%W。该效率高于先前报道的介电超表面的值，并且是在泵浦强度低两个数量级的情况下实现的。这些结果使基于超表面的二次谐波产生向实际应用迈进了一步。
