Polarized three-photon-pumped laser in a single MOF microcrystal.

Higher order multiphoton-pumped polarized lasers have fundamental technological importance. Although they can be used to in vivo imaging, their application has yet to be realized. Here we show the first polarized three-photon-pumped (3PP) microcavity laser in a single host-guest composite metal-organic framework (MOF) crystal, via a controllable in situ self-assembly strategy. The highly oriented assembly of dye molecules within the MOF provides an opportunity to achieve 3PP lasing with a low lasing threshold and a very high-quality factor on excitation. Furthermore, the 3PP lasing generated from composite MOF is perfectly polarized. These findings may eventually open up a new route to the exploitation of multiphoton-pumped solid-state laser in single MOF microcrystal (or nanocrystal) for future optoelectronic and biomedical applications.