Amplified Spontaneous Emission from an MEH-PPV Film in Cylindrical Geometry

We report amplified spontaneous emission (ASE) from a cylindrical capillary structure comprised of a poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV) film deposited on the inside wall of a glass capillary tube. When pumped with a stripe-shaped pulsed laser beam focused onto the capillary edge and parallel to its axis, a collimated and circular-shaped emission emerges from the capillary. The threshold pump power for ASE is about 6 kW/cm2. In the capillary configuration, the emission is unpolarized with spectral linewidth of 8 nm, centered at 638 nm. The glass capillary seems to play an important role in focusing the excitation beam, in waveguiding the emitted radiation, and in protecting the polymer from photo-oxidation