Enhancement of amplified spontaneous emission in organic gain media by the metallic film

•ASE enhancement of organic gain media with Ag film is demonstrated.•ASE threshold of the device is reduced by 3.7 times when Ag film is introduced.•The “half-cavity” effect of Ag film enhances the radiative decay rate, quantum yield and the net gain of media.

Metallic films were widely used in many micro-cavities or as electrodes. However, the quenching of fluorescent molecules and the large absorption loss of metallic films are generally considered fatal for the lasing. We report the enhancement of amplified spontaneous emission (ASE) of organic gain media in planar waveguide structure with metallic film. Compared to the metal-free device, the ASE threshold of device with metallic film is reduced by 3.7 times by introducing the spacer layer between metallic film and organic gain media. It is found that the radiative decay rate, quantum yield of fluorescent molecules and the net gain of media are enhanced by half-cavity effect of Ag film, which lead to the enhanced ASE and lower lasing threshold.

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