As MCQST Distinguished Lecturer, Prof. Pascale Senellart is giving a series of talks targeted to varied audiences. This specialized seminar is designed for researchers working in the same field.

Semiconductor Quantum Dots: From Quantum Light Sources to Quantum Thermodynamics

Abstract

Single-photon sources based on semiconductor quantum dot outperform those based on frequency conversion [1]. Yet, they are still far from ideal operation and the race toward the deterministic source of indistinguishable photons is on. I will discuss our recent efforts along this research line. We first revisited the Hong-Ou-Mandel interference, our main tool to understand the source imperfections [2]. We then developed new tools to control the quantum dot exciton fine structure, a key parameter that controls the source temporal profile [3]. We also exploit acoustic phonon excitation to gain a factor of two in the source efficiency [4] and to generate polarization-frequency hyper-encoded single photons.

Pushing the source technology, our devices have come closer to the text-book atom-photon interface and allow to explore fundamental aspects of light emission process. We revisit spontaneous emission in the framework of quantum thermodynamics. We show that the work exerted by the atom onto the empty cavity mode corresponds to the coherent part of the spontaneously emitted field. At low temperatures, the observed work transfer is close to the theoretical upper bound, a value that is degraded at higher temperatures due to phonon-induced dephasing. We then study the discharge this optical quantum battery onto a classical field and discuss the conditions for maximal work transfer [5].
[1] P. Senellart, G. Solomon and A. White, Nature nanotechnology 12, 1026 (2017)
[2] H. Ollivier et al, Physical Review Letters 126, 063602 (2021)
[3] H. Ollivier et al, in preparation
[4] S. Thomas et al, Physical Review Letters 126 (23), 233601 (2021)
[5] I. Maillette de Buy Wenniger et al, in preparation

About Pascale Senellart

Pascale Senellart is a CNRS research director working in the field of optical quantum technologies. She received her Ph.D. from the University Paris 6 in 2001 and joined the CNRS end of 2002 after two short postdoctoral positions in industrial laboratories. During the first part of her carrier, she explored quantum optics and cavity quantum electrodynamics phenomena in semiconductor systems. On the way, her team developed interesting devices for the generation and manipulation of quantum light. Her group now focuses on the applications of single-photon sources in quantum computing and quantum communications and continues to develop key devices such as sources of many-entangled photons and non-linear gates. Dr. Senellart received the CNRS silver medal in 2014 and was elected OSA Fellow in 2018. In 2017, she cofounded Quandela, a spin-off company specialized in single-photon sources and their applications.

You can follow the group and start-up news on Twitter here: @senellartqd and @quandela_sas