[Seminar] 'Guiding Light to Non-Classicality' by Dr Philipp Schneeweiss

Title: Guiding Light to Non-Classicality

Speaker: Dr Philipp Schneeweiss, Humboldt University, Germany

Abstract:
The interaction between light and matter is an important topic in physics research and relevant to areas ranging from photo synthesis to quantum communication. One of the most fundamental settings is the scattering of a coherent laser beam on a single quantum emitter. A peculiarity of this interaction is that the scattered light never contains two photons at the same time, i.e., it is showing photon-antibunching. In my talk, I will show that photon-antibunching arises from quantum interference between two types of two-photon scattering processes, typically referred to as coherent and incoherent scattering. By spectrally rejecting the coherently scattered part of the fluorescence light from a single two-level atom, we show experimentally that the remaining part of the light consists of photon pairs that have been simultaneously scattered by the emitter [1]. Furthermore, by transmitting a guided laser light field through an ensemble of cold atoms coupled to an optical nanofiber, we demonstrate a collective enhancement of this two-photon scattering process [2]. By changing the dispersion and the optical depth of the atomic ensemble, we can tailor the second-order correlation function of the transmitted light and adjust its photon statistics from photon bunching to perfect antibunching [3]. Our results contribute to understanding the fundamentals of light-matter interaction and might contribute to developing a novel type of source of non-classical light.

[1] L. Masters et al., Nat. Phot. 17, 972 (2023)
[2] A. S. Prasad et al., Nat. Phot. 14, 722 (2020), News & Views: P. Solano, Nat. Phot. 14, 716 (2020)
[3] M. Cordier et al., Phys. Rev. Lett. 131, 183601 (2023)

Related papers:
Correlating photons using the collective nonlinear response of atoms weakly coupled to an optical mode
Tailoring Photon Statistics with an Atom-Based Two-Photon Interferometer

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