Plastic evanescent microlaser

Lasing has been demonstrated in a photopumped microcavity via evanescent-wave-coupledgain. A 50-mu m-diameter unclad quartz fiber is coated with a polymer gain layer having a refractive index lower than that of the quartz fiber. Upon pulsed photoexcitaiton, the cylindrical microcavity exhibits whispering-gallery-mode lasing. A spectral analysis shows that the resonance inside the quartz fiber is responsible for the occurrence of lasing in the orange-red region of the spectrum. The proposed scheme allows the cavity resonant modes to achieve optical gain through evanescent-wave coupling. This is a step toward a device structure that facilitates current injection lasing. (C) 2011 American Institute of Physics. [doi:10.1063/1.3651294]