Spectral broadening of single colloidal nano-emitter under high excitation
Contact : agnes.maitre@insp.upmc.fr
Funding : Sorbonne Université
keywords : Experimental, Internship M2, Nano Photo-Phononics, Quantum Technology, and Theorical
Gratification : Oui
Team(s) internship page(s) : Acoustics and optics for nanosciences and quantum physics Nonophotonics and quantum optics
Internship description
CdSe/CdS core/shell nanocrystal are excellent bright nano-emitters. At room temperature, they behave as high quantum efficiency single photon source thanks to the electronic confinement and efficient Auger processes. Single photon emission can be described by the recombination of a single exciton within a simple two-level system. Under low excitation power at room temperature, the emission linewidth is approximately Δ𝜆 ≈ 20 nm. However, by increasing the excitation power, emission spectrum broadens dramatically up to Δ𝜆 ≈ 150 nm (Fig1a). Moreover, the emission intensity grows non-linearly with increasing excitation power [1][2]. The two- levels system paradigm fails for interpreting those features. We have recently developed a model based on the radiative recombination of multiple excitonic levels within a single nanocrystal , relying on statistical description[3] of electron and hole populations in a quasi-equilibrium and on their recombination.
During the internship the student will consider different types of nano-emitter, quantum dots or quantum wells, and will study their emission under high excitation. He/She will then analyse the experimental datas using among others Bayesian methods, and extent our theoretical model.
