| A comprehensive review of the recent emergence of semiconducting {dollar}pi{dollar}-conjugated polymers as solid-state laser materials is presented. With the notable exception of semiconducting polymer laser diodes, high performance photonic and electronic devices have been fabricated from semiconducting polymers, with their performance parameters approaching or even surpassing those of their inorganic counterparts in some cases. As the first step in exploring the feasibility of 'plastic' laser diodes, optically pumped stimulated emission, gain, and lasing have recently been observed in over a dozen different semiconducting polymers representing a variety of molecular structures with emission wavelengths spanning the visible spectrum. Resonant structures for providing the feedback required for lasing or gain narrowing in submicron thick films, neat and undiluted, of photoluminescent thin solid films of conjugated polymers include: planar waveguides, microcavities, distributed feedback (DFB) structures, and high-Q microresonators. Lasing and gain narrowing have been compared using two of these structures: waveguides and microcavities. In both cases, the gain narrowing or lasing threshold is at 0.05-0.1 {dollar}mu{dollar}J per 10 ns pulse focused to {dollar}sim{dollar}1.5 mm. Single-mode microcavity lasers are obtained when a microcavity resonance occurs at the wavelength where the gain of the polymer is maximum. High efficiency Stokes-shifted photoluminescence (PL) and high gain are features that make undiluted semiconducting polymers uniquely attractive as solid-state laser materials. These features also make the same polymers attractive as active components in InGaN/semiconducting polymer hybrid LEDs, where the blue emission from the InGaN LED provides the blue component, and simultaneously, serves as the short wavelength pump source for exciting the PL of the polymer film(s). White, green, green-yellow, and yellow emitting InGaN/polymer hybrid LED prototypes have been demonstrated simply by dip-coating pre-packaged blue InGaN LEDs in the appropriate polymer solutions. The possibility of obtaining a new generation of semiconducting polymer laser diodes, obtained either by electrically pumping the semiconducting polymer or the InG N component in a hybrid InGaN/polymer device, is explored. |
