All Optical Switching through Anistropic Gain of CsPbBr3SingleCrystal Microplatelet

Perovskite micro/nanostructures have recentlyemerged as a highly attractive gain material for nanolasers. Toexplore their applications and further improve performance, it isessential to understand the optical gain and the anisotropicproperties. Herein, we obtained high quality CsPbBr3microplatelets(MP) with anisotropic orthorhombic phase. Optical gain ofCsPbBr3single crystal MP was investigated via microscale variablestripe-length measurement. A polarization-dependent optical gainwas observed, and the gain along [002] was larger than that of [1 & minus;10]. The behavior was attributed to the lowest energy transitiondipole moment of [002] induced by the smaller deviation of Br & minus;Pb & minus;Br bond from the perfect lattice. Along the [002] direction, weobtained the optical gain value up to 5077 cm & minus;1, which is the recordvalue ever reported. Moreover, all optical switching of lasing isrealized by periodical polarized excitation. Our results provide new perceptions in the design of novel functional anisotropic devicesbased on perovskite micro/nanostructures