Promotionsvortrag Physik: "Squeezed vacuum states of light from a crystalline whispering gallery mode resonator"

Nov 23
November 23, 2020 9:00 am - 10:30 am
Online Prüfung

Ankündigung des Promotionsvortrags von: Herrn Alexander Otterpohl

Squeezed states of light constitute a subclass of nonclassical light, which can only be described by the laws of quantum mechanics. This special kind of light provides noise characteristics that allow for quantum measurements beyond the standard quantum limit, which is the natural limitation for measurements with standard lasers, for example, and rooted in Heisenberg’s uncertainty relation. The field of applications for squeezed states of light ranges from quantum communication schemes and quantum imaging to quantum-enhanced metrology and more recently to continuous variable quantum computing. The latter in particular demands a compact and low-power source for squeezed states of light in order to allow for the required scalability.

Our here presented approach for such a source is based on a crystalline whispering gallery mode resonator. This type of resonator offers high optical Q-factors together with small mode volumes. In addition, our resonators are made of lithium niobate and hereby offer a huge transparency window from the visible up to the telecom regime and strong nonlinear optical interaction. This renders them a versatile source for generating nonclassical light.

In this thesis, we meet the challenge of generating genuinely single-mode squeezed vacuum states of light in such a crystalline whispering gallery mode resonator. For that, we operate the resonator as a degenerate, doubly resonant optical parametric oscillator below threshold. We report on the generation of 1.4dB of vacuum squeezing at a sideband frequency of 500kHz for only 300µW of incident pump power.

(Vortrag auf Englisch)

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