Pump-controlled directional light emission from random lasers.

The angular emission pattern of a random laser is typically very irregular and difficult to tune. Here we show by detailed numerical calculations that one can overcome the lack of control over this emission pattern by actively shaping the spatial pump distribution. We demonstrate, in particular, how to obtain customized pump profiles to achieve highly directional emission.

Hybrid nanoimprinted laser based on conjugated conductive polymer and nanocrystal quantum dots.

A composite of the conjugate conductive polymer poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and CdSe/ZnS quantum dots (QDs) is utilized for nanoimprinted lasers after drop-casting onto one-dimensional omnidirectional Bragg mirrors. Strong amplified spontaneous emission is observed at the resonances of both the QDs and the polymer. Clearly resolved, low-threshold lasing was found after nanoimprinting of distributed-feedback gratings on the composite surface.