Abstract. Photonic-crystal lasers whose feedback is enhanced by a thin layer of titanium dioxide (TiO₂) have been experimentally investigated. The use of TiO₂ increases the index contrast in the photonic crystal as well as the confinement in the waveguide, resulting in larger feedback of the lasing modes. This allows lower thresholds and much smaller devices. Vertically emitting laser devices, using the methyl-substituted ladder-type poly(p-phenylene) (MeLPPP) as gain material, have been fabricated according to optimized parameters, and the measured dispersion relation of the structures matches excellently with simulations. The devices feature a three to five times lower threshold than devices whose feedback structure is etched directly into the fused silica substrate.

Keywords: photonic crystals, lasers, titanium dioxide, organic materials

Print publication: Issue 4 (April 2006)
Received 10 October 2005, accepted for publication 11 January 2006
Published 27 March 2006