Ultralow-threshold quasi-CW lasing from FAPbBrperovskite first-order DFB laser.

Metal halide perovskites are emerging materials for integrated photonics. Here we report a quasi-CW pumped ultra-low ASE/lasing threshold formamidinium lead bromide (FAPbBr) laser. The laser achieved stable lasing at 555 nm with a full width at half maximum (FWHM) of 0.6 nm, showing a low lasing threshold of 22.6J cmunder 3.5 nanosecond quasi-CW excitation at room temperature. The material also showed an ultra-low ASE threshold of 46J cmunder the same pumping condition. Through polymer doping, we showed that the material's performance can be improved by increasing bimolecular recombination rate with reduced grain size.