Optical Bistability in Nanosilicon with Record Low <i>Q</i>-Factor.

Nishida, Kentaro; Tseng, Po-Hsueh; Chen, Yu-Chieh; Wu, Pang-Han; Yang, Chi-Yin; Yang, Jhen-Hong; Chen, Wei-Ruei; Pashina, Olesiya et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

We demonstrated optical bistability in an amorphous silicon Mie resonator with a size of ∼100 nm and <i>Q</i>-factor as low as ∼4 by utilizing photothermal and thermo-optical effects. We not only experimentally confirmed the steep intensity transition and the hysteresis in the scattering response from silicon nanocuboids but also established a physical model to numerically explain the underlying mechanism based on temperature-dependent competition between photothermal heating and heat dissipation. The transition between the bistable states offered particularly steep superlinearity of scattering intensity, reaching an effective nonlinearity order of ∼100th power over excitation intensity, leading to the potential of advanced optical switching devices and super-resolution microscopy.