An organic semiconductor laser, simply fabricated by UV-nanoimprint lithography (UV-NIL), that is pumped with a pulsed InGaN LED is demonstrated. Molecular weight optimization of the polymer gain medium on a nanoimprinted polymer distributed feedback resonator enables the lowest reported UV-NIL laser threshold density of 770 W cm⁻², establishing the potential for scalable organic laser fabrication compatible with mass-produced LEDs.

A blue-emitting distributed feedback laser based on a star-shaped oligofluorene truxene molecule is presented. The gain, loss, refractive index, and (lack of) anisotropy are measured by amplified spontaneous emission and variable-angle ellipsometry. The waveguide losses are very low for an organic semiconductor gain medium, particularly for a neat film. The results suggest that truxenes are promising for reducing loss, a key parameter in the operation of organic semiconductor lasers. Distributed feedback lasers fabricated from solution by spin-coating show a low lasing threshold of 270 W/cm2 and broad tunability across 25 nm in the blue part of the spectrum.

We report the demonstration of a compact, all-solid-state polymer laser system comprising of a Gallium Nitride (GaN) semiconductor diode laser as the pump source. The polymer laser was configured as a surface emitting, distributed Bragg reflector laser (DBR), based on a novel energy transfer blend of Coumarin 102 and the conjugated polymer poly(2- methoxy-5-(2’-ethylhexyloxy)-1,4-phenylene vinylene). In this configuration, diode pumping was possible both due to the improved quality of the resonators and the improved harvesting of the diode laser light.

A study of the amplified spontaneous emission (ASE) properties of three bisfluorene-cored dendrimers in the solid state is reported. The results show that the dendron type has a strong impact on the photoluminescence quantum yield and affects the ASE threshold, the optical gain, and loss coefficients. Optically pumped distributed feedback lasers operating in the blue spectral region were fabricated by spin coating the dendrimer films on top of a two-dimensional corrugated fused silica substrate. A best lasing threshold of $4.5\mu \mathrm{J}∕{\mathrm{cm}}^2$ and a slope efficiency of 8.3% were obtained, which demonstrate the high potential of these materials for laser applications.

In this work we demonstrate a suspended core microstructured optical fiber-based sensor platform forexplosives detection based on the fluorescence quenching of a surface-attached conjugated polymerpoly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). These fibers allow for strongevanescent field interactions with the surrounding media because of their small core size, and can sam-ple minute liquid volumes. This is the first demonstration of a fluorescent conjugated polymer sensorcapable of measuring liquid explosives samples loaded within an optical fiber. This technique is used toidentify 1,4-dinitrobenzene (DNB), a member of the nitroaromatics family of explosives, in acetone forconcentrations as low as 6.3 ppm in a total sampling volume of 27 nl and to quantify its concentrationusing the fluorescence decay lifetime, requiring an analysis time of only a few minutes.Fenghong Chu, Georgios Tsiminis, Nigel A. Spooner, Tanya M. Monr

Optical pumping conditions for organic solid‐state lasers (OSLs) are discussed with particular emphasis on the use of gallium nitride based light‐emitting diodes (LEDs) as pump sources. LEDs operate in a regime where the pump should be optimized for a short rise time and high peak intensity, whereas fall time and overall pulse duration are less important. Lasers pumped with this approach need to have very low thresholds which can now be routinely created using (one‐dimensional) distributed feedback lasers. In this particular case stripe‐shaped excitation with linearly polarized light is beneficial. Arrays of micron‐sized flip‐chip LEDs have been arranged in an appropriate stripe shape and the array dimensions were chosen such that the divergence of LED emission does not cause a loss in peak intensity. These micro‐LED arrays have successfully been used to pump OSLs with thresholds near 300 W/cm² (∼9 ns rise time, 35 ns pulse duration), paving the way for compact arrays of indirectly electrically pumped OSLs.