Plastic Waveguides Display Laser Emission

Daniel S. Burgess

A group of scientists at Trinity College in Dublin, Ireland, and at Tohoku University in Sendai, Japan, has achieved near-infrared laser emission from a polymer waveguide doped with an organic dye. The work promises applications in the development of compact lasers for use in telecommunications.

The researchers elected to use the commercially available dye LDS821 from Exciton Inc. of Dayton, Ohio, as the active dopant for the device. Poly(1-vinyl-2-pyrrolidone) served as the host material. The doped waveguides were fabricated by drop casting an ethanol solution of the host and dopant onto glass substrates and cleaving the resultant polymer layer after evaporation of the solvent.

When the waveguides were optically pumped with 532-nm light from a pulsed frequency-doubled Nd:YAG laser at a fluence greater than 128 µJ/cm², they produced 820-nm radiation. Exposure to several thousand pump pulses resulted in the photodegradation of the dopant, for which the group hopes to compensate using higher-finesse cavity configurations.