Work

Single-photon controlled phase shifts with colloidal quantum dots at room temperature

Year: 2026

Type: article

Abstract: Quantum logic gates based on quantum electrodynamics (QED) in strong coupling regime between quantum dots and microcavities are key elements for scalable quantum computing and all-optical quantum networks. Here, a single colloidal quantum dot was site-selectively positioned onto a dielectric photonic crystal hybrid microcavity using a soft nanoprobe technique, enabling the study of strong coupling between the colloidal quantum dots and bound states in the continuum in the cavity. By combining photoluminescence spectroscopy, Michelson interferometry, and continuous-wave pump-probe technology, the wavelength- and power-dependent phase shifts were systematically characterized. Controlled π-phase shifts of a single photon were experimentally demonstrated in both single colloidal quantum dot and high-concentration colloidal quantum dots coupled microcavity systems. This work provides an experimental basis for the development of room temperature quantum optoelectronic devices, including quantum phase gates and ultralow power optical switches.

Source: Science Advances

DOI: 10.1126/sciadv.aee1340

Authors: Chai Hu, Wenyi Dai, Yuanyuan Zhou, Haiyu Xu, Jiefei Liu, Xingsheng Xu

Institutions: Institute of Semiconductors, Chinese Academy of Sciences, University of Chinese Academy of Sciences

Language: English

Topic: Strong Light-Matter Interactions

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,500

Funders: National Natural Science Foundation of China, National Science and Technology Major Project