Cavity Engineering of Perovskite Distributed Feedback Lasers

Perovskite distributed feedback (DFB) lasers are gaining increasing attention due to their solution processability, band gap tunability, single-mode operation, and low threshold. However, it is still challenging to fabricate high-quality DFB cavities on perovskite films, resulting in a mismatch between the optical resonance and the gain spectrum. To address these issues, here we develop a systematic facile approach to fabricate and design the cavities of perovskite surface-emitting DFB lasers. Using this approach, the cavity fabrication is simplified by adding polyvinylpyrrolidone into the perovskite precursor solutions, enabling a simple nanoimprint on perovskite films, while the cavity engineering is guided by a systematic optical mode analysis and conducted through simply varying the solution concentration to manipulate the effective index of the waveguide mode. With this methodology, we fabricated perovskite DBF lasers with an optimized optical resonance, whereby a low threshold of 20 μJ cm–2 was achieved. Our approach provides an effective way to fabricate high-performance perovskite DFB lasers. With this technique, we can easily realize high-precision cavity tuning with a precision of better than 5 nm.