Giant photothermal nonlinearity in a single silicon nanostructure

Yi-Shiou Duh,Pang-Han Wu,Jhen-Hong Yang,Hou-Xian Ding,Kuo-Ping Chen,Katsumasa Fujita,Ikuto Hotta,Shi-Wei Chu,Hao-Yu Cheng,Yu-Lung Tang,Kentaro Nishida,Yusuke Nagasaki,Chih-Wei Chang,Te-Hsin Yen,Yu-Ping Lo,Junichi Takahara,Kung-Hsuan Lin

doi:10.1038/s41467-020-17846-6

Abstract

Silicon photonics have attracted significant interest because of their potential in integrated photonics components and all-dielectric meta-optics elements. One major challenge is to achieve active control via strong photon–photon interactions, i.e. optical nonlinearity, which is intrinsically weak in silicon. To boost the nonlinear response, practical applications rely on resonant structures such as microring resonators or photonic crystals. Nevertheless, their typical footprints are larger than 10 μm. Here, we show that 100 nm silicon nano-resonators exhibit a giant photothermal nonlinearity, yielding 90% reversible and repeatable modulation from linear scattering response at low excitation intensities. The equivalent nonlinear index is five-orders larger compared with bulk, based on Mie resonance enhanced absorption and high-efficiency heating in thermally isolated nanostructures. Furthermore, the nanoscale thermal relaxation time reaches nanosecond. This large and fast nonlinearity leads to potential applications for GHz all-optical control at the nanoscale and super-resolution imaging of silicon.

Highlights

Silicon photonics have attracted significant interest because of their potential in integrated photonics components and all-dielectric meta-optics elements
In the field of silicon photonics, one particular emphasis is placed on achieving all-optical control, which requires strong photon–photon interactions or optical nonlinearity[3,4]
We discovered a large and fast photothermal nonlinearity of Si nanostructures, enabled by Mie-resonance enhanced absorption and thermally isolated efficient heating

Summary

Introduction

Silicon photonics have attracted significant interest because of their potential in integrated photonics components and all-dielectric meta-optics elements. To boost the nonlinear response, practical applications rely on resonant structures such as microring resonators or photonic crystals. Their typical footprints are larger than 10 μm. The nanoscale thermal relaxation time reaches nanosecond This large and fast nonlinearity leads to potential applications for GHz all-optical control at the nanoscale and super-resolution imaging of silicon. Because of its indirect bandgap, Si has limited applications in photonics It is a long-awaited goal to combine photonics with the advantages of silicon. Because of the weak nonlinearity of Si, the typical design of nonlinear silicon photonic components requires resonant structures such as microring resonators and photonic crystals[6,7]

Methods

Results

Conclusion