Two-photon-excited fluorescence spectroscopy of Rb atoms in a magneto-optical trap
Researchers used two-photon-excited fluorescence spectroscopy (TPEF) on ultracold Rubidium atoms cooled in a magneto-optical trap (MOT). They successfully measured power dependence down to very low excitation levels, achieving unprecedented flux sensitivity. This demonstrates that ultracold Rb is an excellent platform for detecting sensitive, low-flux two-photon phenomena like Entangled Two-Photon Absorption (ETPA).