Gain narrowing in optically pumped thin films, both neat and undiluted, of luminescent conjugated polymers with different molecular structures was demonstrated. These results indicate that the polymers studied have large cross sections for stimulated emission, that population inversion can be achieved at low pump energies, and that the emitted photons travel distances greater than the gain length within the gain medium. The use of simple waveguide structures is sufficient to cause low gain narrowing thresholds in submicrometer-thick films.

No abstract

No abstract

No abstract

We report white light emission from InGaN/conjugated polymer hybrid light-emitting diodes (LEDs). White light sources (or sources with various colors) are achieved by combining the photoluminescence (PL) from semiconducting (conjugated) polymers with the emission from high efficiency InGaN based LEDs; the InGaN based LED provides the blue component and, simultaneously, serves as the short wavelength pump source for exciting the PL of the polymer film(s).

We have fabricated photopumped distributed feedback lasers by spin-casting thin films of the semiconducting polymer poly͑2-butyl, 5-͑2Ј-ethyl-hexyl͒-1,4-phenylenevinylene͒ over gratings in silicon oxide. The lasers have two modes that each have a linewidth of 0.2 nm. The lasing wavelength was tuned from 540 to 583 nm by adjusting the period of the gratings.

Gain narrowing and lasing from a soluble, highly photoluminescent conjugated polymer, poly(2-butyl, 5-(2′-ethyl-hexyl)-1,4-phenylene vinylene) (BuEH-PPV), are compared using two resonant structures: planar waveguides and microcavities. The gain narrowing and lasing thresholds are comparable, 0.05–0.1 μJ (10 ns pulse focused to ∼1.5 mm). Gain narrowing is not observed in films on indium tin oxide (ITO) unless a cladding layer is placed between the BuEH-PPV and ITO. Single-mode microcavity lasers are obtained when a cavity resonance occurs at the wavelength where the gain of the polymer is maximum.

No abstract