Dendrimer Lasers

Dendrimer lasers have as their active medium fluorescing dye molecules lodged at the heart of hyper-structured, tree-shaped polymers (see figure). In most dye lasers the dye concentration cannot go above a millimole/liter without quenching the fluorescence process. But in a new experiment by scientists at the Communications Research Laboratory and PRESTO Japan Science and Technology Corporation, both in Japan, a dye concentration of 9 millimoles/liter showed no diminution of laser output, but rather an increase. Furthermore, the spectral linewidth (the spread in wavelengths) is narrow, only 0.1 nm. The laser output was so potent that end mirrors were not used. This, combined with other organic-laser properties such as flexibility and tunability, will soon result in 100-nm-sized lasers. The researchers (Shiyoshi Yokoyama, 81-789-692-254, syoko@crl.go.jp) are now at work on extending their dendrimer structures in producing solid state waveguides, fibers, and photonic crystals. (Yokoyama et al., Applied Physics Letters, 7 Jan 2002.)