# Enhanced optical bistability in slotted photonic crystal structure for microwave frequency generation

## TL;DR

This paper introduces a new silicon-based nanocavity design that enhances optical bistability and generates microwave frequencies efficiently.

## Contribution

The novel slotted photonic crystal nanocavity design achieves ultra-high quality factors and low power thresholds for optical bistability and microwave generation.

## Key findings

- The cavity achieves a quality factor of 2.15 × 10⁶ and a modal volume of 0.18 μm³.
- Optical bistability occurs at a low threshold power of 2 μW under specific detuning conditions.
- Microwave frequencies up to 21.34 GHz are generated through self-pulsing oscillations.

## Abstract

This study proposes a novel silicon nanocrystal SiNC/SiO\documentclass[12pt]{minimal}
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\begin{document}$${}_{2}$$\end{document} embedded slotted photonic crystal nanocavity employing precise width modulation to explore optical bistability and self-pulsing behavior for microwave signal generation. The designed cavity achieves an ultra-high quality factor (Q) of \documentclass[12pt]{minimal}
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\begin{document}$$2.15 \times 10^6$$\end{document} and a low modal volume of \documentclass[12pt]{minimal}
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\begin{document}$$0.18 \, \mu m^3$$\end{document}. Theoretical modeling incorporating Kerr nonlinearity, two-photon absorption, and free carrier effects is used to analyze the bistability response. Simulation results reveal a low threshold power of \documentclass[12pt]{minimal}
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\begin{document}$$2 \mu W$$\end{document} for optical bistability under a − 20 pm detuning condition. Additionally, the cavity demonstrates microwave frequency generation through self-pulsing oscillations, with a fundamental mode and observable second harmonic at 21.34 GHz. Fabrication tolerance is also evaluated, showing that the design sustains performance with up to 9% randomness in hole radii, 12% in x-position, and 20% in z-position of air holes. These findings confirm the feasibility of the proposed structure for low-power, high-frequency integrated photonic applications.