Ali Rana Faryad, Busche Jacob A, Kamal Saeid, Masiello David J, Gates Byron D
Department of Chemistry and 4D LABS, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
Department of Chemistry, University of Washington, Seattle, WA, 98195, USA.
Light Sci Appl. 2023 Apr 25;12(1):99. doi: 10.1038/s41377-023-01092-8.
Nanophotonics research has focused recently on the ability of nonlinear optical processes to mediate and transform optical signals in a myriad of novel devices, including optical modulators, transducers, color filters, photodetectors, photon sources, and ultrafast optical switches. The inherent weakness of optical nonlinearities at smaller scales has, however, hindered the realization of efficient miniaturized devices, and strategies for enhancing both device efficiencies and synthesis throughput via nanoengineering remain limited. Here, we demonstrate a novel mechanism by which second harmonic generation, a prototypical nonlinear optical phenomenon, from individual lithium niobate particles can be significantly enhanced through nonradiative coupling to the localized surface plasmon resonances of embedded gold nanoparticles. A joint experimental and theoretical investigation of single mesoporous lithium niobate particles coated with a dispersed layer of ~10 nm diameter gold nanoparticles shows that a ~32-fold enhancement of second harmonic generation can be achieved without introducing finely tailored radiative nanoantennas to mediate photon transfer to or from the nonlinear material. This work highlights the limitations of current strategies for enhancing nonlinear optical phenomena and proposes a route through which a new class of subwavelength nonlinear optical platforms can be designed to maximize nonlinear efficiencies through near-field energy exchange.
纳米光子学研究近来聚焦于非线性光学过程在众多新型器件中调控和转换光信号的能力，这些器件包括光调制器、换能器、滤色器、光电探测器、光子源以及超快光开关。然而，较小尺度下光学非线性固有的弱点阻碍了高效小型化器件的实现，并且通过纳米工程提高器件效率和合成通量的策略仍然有限。在此，我们展示了一种新机制，通过这种机制，单个铌酸锂颗粒产生的二次谐波产生（一种典型的非线性光学现象）可通过与嵌入的金纳米颗粒的局域表面等离子体共振进行非辐射耦合而显著增强。对涂覆有一层直径约为10 nm的分散金纳米颗粒的单个介孔铌酸锂颗粒进行的联合实验和理论研究表明，在不引入精细定制的辐射纳米天线来介导光子与非线性材料之间的转移的情况下，二次谐波产生可实现约32倍的增强。这项工作突出了当前增强非线性光学现象策略的局限性，并提出了一条途径，通过该途径可以设计一类新的亚波长非线性光学平台，以通过近场能量交换最大化非线性效率。
