SPECTRAL DIFFUSION AND THE STARK EFFECT IN COLLOIDAL QUANTUM DOTS

SPECTRAL DIFFUSION AND THE STARK EFFECT IN COLLOIDAL QUANTUM DOTS

07/01/2023

Chemistry Faculty Seminar Room

12:30PM

Dr. Ron Tenne University of Konstanz, Germany

Physical-Chemistry Seminar

Candidate seminar

Spectral diffusion and the Stark effect in colloidal quantum dots

While colloidal quantum dots (CQDs) have become an important building block in electro-optical devices, in the realm of quantum science and technology, they are often considered inferior to other types of quantum emitters such as solid-state defects and epitaxial quantum dots. Despite their single-photon emission [1], demonstrations of quantum coherence and control are largely still lacking. The main obstacle towards these is spectral diffusion – stochastic fluctuations in the energy of photons emitted from an individual CQD even at cryogenic temperatures. In this talk, I will present our recent work providing, for the first time, direct and definitive proof that these fluctuations arise from stochastic electric fields in the micro environment [2]. The high sensitivity of CQDs to electric fields, through the quantum-confined Stark effect, is not only a bug but also a feature – broadband coherent control of the temporal wavefunction of the emitted photon. To fulfill the unique potential that CQDs hold in the field of quantum optics, spectroscopy at fast-to-ultrafast (milliseoncd-to-femtosecond) timescales, relying on tools from terahertz and femtosecond-laser toolboxes [3,4], will play a detrimental role.