Low power optical bistability from quantum dots in a nanobeam photonic crystal cavity

Abstract

We demonstrate a low power thermally induced optical bistability at telecom wavelengths and room temperature using a nanobeam photonic crystal cavity embedded with an ensemble of quantum dots. The nanobeam photonic crystal cavity is transfer-printed onto the edge of a carrier chip for thermal isolation of the cavity with an efficient optical coupling between the nanobeam waveguide and optical setup. Reflectivity measurements performed with a tunable laser reveal the thermo-optic nature of the nonlinearity. A bistability power threshold as low as 23 μW and an on/off response contrast of 6.02 dB are achieved from a cavity with a moderately low quality factor of 2830. Our device provides optical bistability at power levels an order of magnitude lower than previous quantum-dot-based devices.

Quality factor enhancement of InP nanobeam cavities using atomic layer deposition

“…Photonic crystal nanobeam cavities have garnered significant attention due to their exceptional ability to confine light both spatially and temporally, making them highly advantageous for various low-power photonic applications, including quantum information processing [1], nonlinear optics [2,3], and photonic integrated circuits [4]. Achieving strong lightmatter interactions requires fabricating cavities with small mode volumes (V) and large Q factors, resulting in a high Q/V ratio.…”