Room‐Temperature Single‐Mode Plasmonic Perovskite Nanolasers with Sub‐Picosecond Pulses

Abstract With the explosive growth of communication traffic, increasing the modulation bandwidth of semiconductor lasers has attracted significant attention. However, after rapid progress is achieved, further increasing the modulation bandwidth of semiconductor lasers is hampered by the slow charge‐carrier dynamics. Here, a room temperature, single‐mode perovskite nanolaser with sub‐picosecond pulses, enabled by high Purcell enhancement is reported. This enhancement is achieved via transferring an atomically smooth perovskite nanoplatelet onto the surface of an ultra‐smooth SiO 2 /Ag film. This nanolaser features a low mode volume (V) as low as 0.137 µm 3 , a high‐quality factor (Q) up to 2180, and a low lasing threshold of 36.65 µJ cm −2 . The Q value of the laser is one order of magnitude higher than that of state‐of‐the‐art nanolasers. The smoothness of both the nanoplatelet and the SiO 2 /Ag film in the laser is critical to achieving a high Purcell enhancement. Polarization analysis reveals that the laser emission consists of a transvere‐magnetic (TM) polarized surface plasmon mode and a transverse‐electric (TE) polarized photonic mode. Furthermore, ultrafast charge‐carrier dynamics indicate the surface plasmon decay time can be as short as 0.6 ± 0.4 ps due to the high Purcell enhancement. This work opens up the possibility of developing nanolasers with high bandwidths and ultra‐small sizes.