Gao Yang, Ling Cheng, Weng Danyi, Rui Guanghao, He Jun, Cui Qiannan, Xu Chunxiang, Gu Bing
School of Electronic Science & Engineering, Southeast University, Nanjing 210096, China.
School of Physics, Tonghua Normal University, Tonghua 134000, China.
Nanoscale. 2024 Oct 3;16(38):18046-18055. doi: 10.1039/d4nr03099k.
With the increasing demand for high-performance passive nonlinear photonic devices, significant progress has been made in spatial self-phase modulation (SSPM) based on 2D nanomaterials in all-optical switches, logic gates, and information converters in recent years. However, there are still challenges in improving the responsiveness of photonic devices. In this work, we prepared a heterojunction of Ag nanoparticles deposited on the surface of violet phosphorus nanosheets (VP Ns), investigated their SSPM, and demonstrated their performance in all-optical switches. The SSPM experimental results show that compared with pure VP Ns at the same light intensity, both the maximum number and the formation time of self-diffraction rings in Ag/VP heterojunctions increase, and the nonlinear refractive index is approximately doubled. The main reason for optical nonlinearity enhancement is that the internal electric field in the heterojunction strengthens the mobility of the photogenerated carrier, thereby enhancing its optical nonlinearity. In particular, we demonstrate the performance of all-optical switches based on SSPM by utilizing the superior optical nonlinearity of Ag/VP heterojunctions. It is shown that with the increase of low-dose Ag content in heterojunctions, the switching time in the all-optical switch becomes shorter and the maximum number of self-diffraction rings of the signal light increases, although the quality of self-diffraction rings slightly decreases due to the scattering of Ag particles. The results contribute to the design and implementation of high-performance nonlinear photonic devices, based on the use of heterojunctions with low-cost preparation and a high nonlinear refractive index.
随着对高性能无源非线性光子器件的需求不断增加，近年来基于二维纳米材料的空间自相位调制（SSPM）在全光开关、逻辑门和信息转换器等方面取得了显著进展。然而，在提高光子器件的响应度方面仍存在挑战。在这项工作中，我们制备了沉积在紫磷纳米片（VP Ns）表面的银纳米颗粒异质结，研究了它们的SSPM，并展示了它们在全光开关中的性能。SSPM实验结果表明，与相同光强下的纯VP Ns相比，Ag/VP异质结中自衍射环的最大数量和形成时间均增加，且非线性折射率大约翻倍。光学非线性增强的主要原因是异质结中的内电场增强了光生载流子的迁移率，从而增强了其光学非线性。特别是，我们利用Ag/VP异质结优异的光学非线性展示了基于SSPM的全光开关性能。结果表明，随着异质结中低剂量Ag含量的增加，全光开关中的开关时间变短，信号光的自衍射环最大数量增加，尽管由于Ag颗粒的散射，自衍射环的质量略有下降。这些结果有助于基于低成本制备和高非线性折射率的异质结设计和实现高性能非线性光子器件。
