Frequency upconversion lasers using low-dimensional perovskites

Low-dimensional perovskites have been demonstrated with superb multiphoton absorption capabilities and exceptional emission characteristics, benefiting from quantum confinement effect together with their peculiar crystallographic and electronic structures. Moreover, low-threshold and broadband frequency upconversion amplified spontaneous emission has been achieved in low-dimensional perovskites taking advantage of their essential virtues of preeminent multiphoton absorption and photoluminescence properties, low defect density, defect-tolerant electronic structures, relatively slow Auger recombination, remarkable optical gain attributes, broadband tunability, and so on. Making use of external cavities, photostable and low-threshold frequency upconversion lasing with superior spatial and temporal coherence than ASE has been implemented using low-dimensional perovskites. What's more, low-dimensional perovskites themselves have served as excellent cavity resonators to realize photostable frequency upconversion lasing with low threshold and gigantic quality factor, thanks to the great reflectance at interface, small critical angle, small scattering, which originate from high crystalline quality, low defect density, smooth outer facets, and large refractive indices. These enable low-dimensional perovskites excellent candidates for renovating frequency upconversion lasers.