  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
photo-toxicity. 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 was developed and its key characteristics analysed. To demonstrate
its suitability as key component for imaging experiments, the entangled
two-photon absorption behavior of CdSe/ZnS quantum dot solutions was
experimentally investigated.
