Single Crystal Microrod Based Homonuclear Photonic Molecule Lasers

Homonuclear photonic molecules are essential platforms to tailor and manipulate light in micro- and nanoscales. While photonic molecule microlasers have been widely explored in the past two decades, the unavoidable fabrication deviations make their resonant units hard to be identical and, thus, the corresponding practical applications are hindered by the experimental realization. Herein, the authors experimentally demonstrate a novel and effective approach to achieve homonuclear photonic molecule lasers with the synthesized single crystalline CH₃NH₃PbBr₃ perovskite microwires. A single crystalline microwire is cut into two segments that are placed shoulder by shoulder in proximity. Due to their naturally flat facets and uniformity, the transverse whispering-gallery-mode lasers in two parts are almost the same and can naturally couple each other via evanescent waves. Consequently, bonding and antibonding modes are successfully achieved in many similar systems without applying any external controls. All of these experimental observations are consistent with the photonic molecule theory and are confirmed with numerical calculations. This research can be applied to all bottom-up synthesized microwires and, thus, will open a new avenue of bottom-up synthesized microrods to quantum optics and photonic circuits.