Solid-State Rhodamine 6G Microcavity Laser

In this letter, we demonstrate lasing from Rhodamine 6G in a microcavity organic vertical cavity surface emitting laser (VCSEL) in solid state. We adopted an original approach to forming thin films of Rhodamine 6G doped into a poly(methyl methacrylate) (PMMA) host matrix and to integrating them in a dielectric microcavity architecture. We dissolved the materials in dimethylformamide and then spin coated the gain layer onto a planar dielectric mirror in an anhydrous environment to prevent premature precipitation of the PMMA. The second dielectric mirror was positively curved and was positioned on top of the gain layer to form a VCSEL with a tunable cavity resonance and a quality factor exceeding $Q = 1500$ . We optically excited the device through one of the cavity resonances using femtosecond pulses and observed lasing above a threshold of $17 \pm 3 ~\mu \text{J}$ /cm 2 of absorbed energy. The lasing emission followed the polarization of the pump and narrowed from 0.85 to 0.05 nm.