Photon Pair Source based on PPLN-Waveguides for Entangled Two-Photon Absorption

Fluorescence excitation by absorption of entangled photon pairs offers benefits compared to classical imaging techniques, such as the attainment of higher signal levels at low excitation power while simultaneously mitigating phototoxicity. However, current entangled photon pair sources are unreliable for fluorescence detection. In order to address this limitation, there is a need for ultra-bright entangled photon pair sources. Among the potential solutions, sources utilizing nonlinear waveguides emerge as promising candidates to facilitate fluorescence excitation through entangled photons. In this paper, a source consisting of a periodically poled lithium niobate waveguide is developed and its key characteristics are analyzed. To demonstrate its suitability as key component for imaging experiments, the entangled two-photon absorption behavior of Cadmium Selenide Zinc Sulfide quantum dot solutions is experimentally investigated. Fluorescence excited by absorption of entangled photons can enable a new generation of microscopes. This article introduces an entangled photon pair source based on a periodically poled lithium niobate waveguide as promising candidate to facilitate fluorescence through entangled photons. To demonstrate its suitability as key component, the entangled two-photon absorption behavior of CdSe/ZnS quantum dot solutions is investigated. image