  Solution-processed lead halide perovskites have shown very bright future in
both solar cells and microlasers. Very recently, the nonlinearity of
perovskites started to attract considerable research attention. Second harmonic
generation and two-photon absorption have been successfully demonstrated.
However, the nonlinearity based perovskite devices such as micro- & nano-
lasers are still absent. Here we demonstrate the two-photon pumped nanolasers
from perovskite nanowires. The CH3NH3PbBr3 perovskite nanowires were
synthesized with one-step solution self-assembly method and dispersed on glass
substrate. Under the optical excitation at 800 nm, two-photon pumped lasing
actions with periodic peaks have been successfully observed at around 546 nm.
The obtained quality (Q) factors of two-photon pumped nanolasers are around
960, and the corresponding thresholds are about 674?J=cm2. Both the Q factors
and thresholds are comparable to conventional whispering gallery modes in
two-dimensional polygon microplates. Our researches are the first
demonstrations of two-photon pumped nanolasers in perovskite nanowires. We
believe our finding will significantly expand the application of perovskite in
low-cost nonlinear optical devices such as optical limiting, optical switch,
and biomedical imaging et al.
