Promotionsvortrag Physik: Towards photon pair generation via spontaneous four-wave mixing in nonlinear metasurfaces

Ankündigung des Promotionsvortrags von: Herrn Changjin Son

Entangled photons have acted as a workhorse in many quantum technologies, including cryptog-raphy, imaging, sensing, and computation. With the growing demands of quantum technology, the entangled photon pair sources are required to be compact and integrable. For the last few years, the field of quantum optics in the nanoscale has demonstrated photon pair generation in 'flat' optics such as thin layers, Van der Waals crystals, micro-, nano-antennas, and metasurfaces. The word 'flat' is used because such optical platforms have sub-wavelength thicknesses. Due to the short travel length inside the sources, they can possess multiple functions that their bulky coun-terparts cannot have.

This presentation addresses photon pair generation in 'flat' optics via second- and third-order non-linear processes, which are spontaneous parametric down-conversion (SPDC) and spontaneous four-wave mixing (SFWM). The main aims of this presentation are to understand how the photon pair generation is realized via SPDC and SFWM on subwavelength-scale platforms, and to make a bridge between photon pair generation via two nonlinear processes under the presence of opti-cal resonances.

The topic of the presentation covers SPDC in a gallium phosphide (GaP) metasurface, SFWM in a thin lithium niobate (LN) layer and silicon-rich silicon nitride layers, and, finally, fabrication of a metasurface for the SFWM for future work.

(Vortrag auf Englisch)

Dem Vortrag schließt sich eine Diskussion von 15 Minuten an. Vortrag und Diskussion sind öffentlich. Diesen Verfahrensteilen folgt ein nicht öffentliches Rigorosum von 45 Minuten.