Abstract
Capitalizing on the success of the microelectronics and integrated photonics industries, silicon is the material that has generated the most scientific interest for quantum technologies and currently offers the greatest diversity of integrated quantum systems. Recently, in 2020, a new type of physical systems in silicon has emerged for quantum applications: individual color centers. These fluorescent point defects can be isolated at single defect-scale using low-temperature confocal microscopy, and emit single photons directly at telecom wavelengths, suitable for long-distance propagations in optical fibers. Furthermore, some of these defects are also coupled to an optically detectable electron spin that could be used to store and process quantum information.
In this presentation, we will review the recent developments of this rapidly growing field of research. We will then focus on a specific carbon-based defect, called the G center, that behaves as a rotating pseudo-molecule trapped in the silicon material. Using optically-detected spin spectroscopy, we will demonstrate the coherent control of the electron spin state of single G centers integrated in silicon-based microphotonic cavities. Our findings highlight an unusual phenomenon of single spin tumbling, where the defect spin principal axes jump over time between discrete orientations in the crystal.
