Quantum optics with hot atoms

Strong interactions between atoms are known to cause nonlinearities at a few photon

level, which are crucial for applications in quantum optics, communication and computation. The question is whether this can be achieved with a thermal vapor of Alkali atoms at room (or elevated) temperature. We pursue a twofold approach to reach this goal: 1) by increasing the interaction strength between the atoms with Rydberg atoms, and 2) by increasing the interaction strength between the atoms by bringing them closer together. In the first case we exploit the Rydberg blockade effect in combination with a small excitation volume to generate single photons. This has been achieved in a first generation experiment [1] and we will report how we will improve our single photon source in an ongoing experiment. The second research line combines high densities and photonic structures to harvest the light induced dipole-dipole interaction. With the help of nanoscopic waveguides and resonators we can improve the atom light interaction and at sufficient densities also the atom-atom interaction. Especially an enhanced Purcell factor can amplify the light induced dipole-dipole interaction [2].



[1] F Ripka, et al., A room-temperature single-photon source based on strongly interacting Rydberg atoms, Science 362 (6413), 446-449 (2018)



[2] Skljarow et al., Purcell-enhanced dipolar interaction in nanostructures, arXiv:2112.11175

(2021)