Hybrid Atomic-Photonics: New Paradigm for Integrated Quantum Optics

DIPC Seminars

Hadiseh Alaeian, Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
Donostia International Physics Center
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Hybrid Atomic-Photonics: New Paradigm for Integrated Quantum Optics Atoms with narrow-line resonances play a major role in high precision measurements like magnetometry and atomic clocks. Due to their long inherent coherence time, atoms can serve as quantum memories as well. Moreover, as they possess well-defined electronic levels, coherent interactions with the photon fields can be used to manipulate their quantum states very precisely. Besides, the capability of the optical excitation and read out, increase the spatial resolution of the atomic sensors. Within the last couple of decades interfacing atoms with engineered confined light fields has been a proper playground for investigating various quantum- electrodynamical effects. So far different strategies have been utilized successfully to integrate atoms with a confined light field, for example in high-finesse optical cavities, hollow core fibers, and tapered nanofibers. While cold atom setups provide ideal conditions and controllability to explore different coupling regimes, the large setups required to cool and trap the atoms have hindered their scalability for any realistic quantum networks. Thermal vapors, on the other hand, allow for less precision and control, but their low technical complexity and suitable compatibility with miniaturization and integration make them a promising candidate for realizing scalable networks. In this talk, I review our recent results on integrated thermal vapors with engineered light fields. Since the velocity of the atoms in a thermal vapor limits their coherence times a larger coupling rate is required to control the atoms efficiently. To achieve a larger Rabi frequency while still having reasonable laser power we have used Nano-photonic devices with tightly- focused electromagnetic fields and small mode-volumes. In particular, we have investigated the interaction between atomic transitions in the thermal vapor of rubidium (Rb) and optical modes of Si3N4 waveguides, ring resonators, and Mach-Zehnder interferometers. Moreover, I will briefly introduce the Monte-Carlo simulation method that has been developed in our group to model the interaction of the atoms with the device by properly incorporating the surface effects via Casimir- Polder potentials. In addition to the tailored atom-light manipulations, strong atom-atom interactions in particular between Rydberg atoms can be used to realize quantum devices and strong nonlinearities. Utilizing these features, we demonstrate a completely new single-photon source that benefits from four-wave mixing and Rydberg blockade to generate single photons in an on-demand time window. Besides, I will present some of our most recent results on two-photon spectroscopy and its potential and promise for compatibility with the well- established silicon photonics technology. The talk will be concluded with some of our ideas and perspectives for using this platform for cavity QED studies and devising new schemes for investigating atom-atom interactions in a low-dimensional light field.