Picosecond Random Lasing Based on Three-Photon Absorption in Organometallic Halide CH3NH3PbBr3 Perovskite Thin Films

Organometallic halide perovskites have been demonstrated to be very promising for nonlinear optics and practical frequency upconversion devices in integrated photonics. In this work, high quality organometallic halide CH3NH3PbBr3 perovskite thin films were synthesized through a solution-based one-step spin-coating method. With femto-second optical pumping at 1300 nm, frequency-upconverted random lasing (RL) from the bromide perovskite films were achieved via three-photon (3P) absorption processes. The RL spectra show no spikes due to the large scattering mean-free path in the perovskite crystals, meaning the incoherent RL emission with incoherent feedback. In comparison with the one-photon pumped situation, it is found that both the two-photon and 3P excitations are more effective in reducing the RL threshold, despite the low conversion efficiency of their nonlinear multiphoton schemes. Moreover, the time- and spectral-resolved lasing characteristics of the laser pulses were systematically explored by time-resolved photoluminescence based on an optical Kerr-gate method. The measured ultrashort 3.1 ps output pulse is the shortest one that has been observed so far in bromide perovskite random lasers, without any postprocessing. In addition, wavelength dependence of the pulse width and delay time of the RL pulses were clearly demonstrated, and could be unravelled by intraband carrier relaxation dynamics, which is an important physical mechanism in ultrafast lasers. Our results demonstrate that organometallic halide perovskites are excellent gain medium for high-performance frequency upconversion random lasers and have great potential for use in gain-switched semiconductor lasers with ultrashort output pulses and tunable emission wavelengths across the entire visible spectrum.