Tailoring Single‐Mode Random Lasing of Tin Halide Perovskites Integrated in a Vertical Cavity

The development of random lasing (RL) with predictable and controlled properties is an important step to make these cheap optical sources stable and reliable. However, the design of tailored RL characteristics (emission energy, threshold, number of modes) is only obtained with complex photonic structures, while the simplest optical configurations able to tune the RL are still a challenge. This work demonstrates the tuning of the RL characteristics in spin‐coated and inkjet‐printed tin‐based perovskites integrated into a vertical cavity with low quality factor. When the cavity mode is resonant with the photoluminescence (PL) peak energy, standard vertical lasing is observed. More importantly, single mode RL operation with the lowest threshold and a quality factor as high as 1 000 (twenty times the quality factor of the resonator) is obtained if the cavity mode lies above the PL peak energy due to higher gain. These results can have important technological implications toward the development of low‐cost RL sources without chaotic behavior. This work demonstrates the tuning of the Random Lasing (RL) characteristics in spin‐coated and inkjet‐printed tin‐based perovskites integrated into a vertical cavity. When the cavity mode is resonant with the photoluminescence (PL) peak energy, standard vertical lasing is observed, while single‐mode RL is obtained if the cavity mode lies above the PL peak energy.