Promotionsvortrag Physik: „Generation of entangled photons strongly separated in frequency through four-wave mixing in noble gas-filled hollow-core fibers“

Ankündigung des Promotionsvortrags von: Herrn Santiago López-Huidobro

This PhD presentation addresses the development and characterization of two tunable fiber-based biphoton sources with exceptional frequency separation between the entangled photons. The biphoton sources were built using xenon-filled hollow-core photonic crystal fibers (HC-PCFs) via four-wave mixing. This work demonstrates the first tunable biphoton source with one photon in the UV-C and its entangled counterpart in the near-infrared (near-IR) spectral range. This novel source enabled pioneering steps toward UV spectroscopy using undetected photons, laying the groundwork for a transformative approach in quantum sensing technologies. Spectroscopy with undetected photons, based on induced coherence, allows for probing of materials at one fre-quency while detecting the entangled photons at another frequency, offering advantages over traditional methods.

I begin by introducing the development of a fiber-based biphoton source with exceptionally broad frequency tunability. This source can be tuned covering the visible to near-IR spectrum. Secondly, I exhibit the creation of the first biphoton source with one photon in the UV-C and its entangled partner in the near-IR spectral range. The frequency tunability of this source is ~192 THz. Finally, I present the construction of a nonlinear interferometer capable of operating across UV-C, visible, and near-IR spectral ranges. I confirmed the detection of interference from near-IR photons by shifting the phase of the entangled UV-C photons. This advancement expands the range of inves-tigation, as existing sensing methods with undetected photons have so far been limited to the mid-IR to terahertz spectral regions.

(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.