Improved optical confinement in ambipolar field-effect transistors toward electrical injection organic lasers

Abstract

Increasing optical confinement is critical to lowering laser thresholds and increasing modal gain in semiconductor lasers. Here, mode-solver calculations are used to demonstrate that improvements to optical confinement are possible in organic field-effect transistor geometries by using high refractive index cladding layers. Optical experiments show that the proposed structure increases the efficiency of amplified spontaneous emission (ASE) and lowers ASE thresholds without incurring additional losses. The results suggest that the structure can be used to improve optical confinement for both optically pumped, and electrical injection organic lasers where thin, low refractive index active materials are required.