| Popis: |
Molecular sieves, such as nanoporous AlPO4-5, can host a wide variety of laser-active dyes. Slim dyes like Coumarin40 or Oxazine 1, fitting into the channel pores, as well as bulky dyes like rhodamines and Oxazine 750, being located in defect sites of the molecular sieve structure, are embedded during microwave-assisted crystallization. The fast microwave-assisted crystallization offers a new procedure for the stable and monomeric encapsulation of organic dyes into molecular sieves without any degradation of the chromophores and enables the control of the morphology of the host material. Based on this class of materials a new form of microlasers has been created. Their properties depend on size and shape of the molecular sieve crystals. The microcrystals act as hexagonal ring resonators (whispering gallery mode). In dependence on the morphology of the crystals different laser properties have been observed in agreement with theoretical predictions. Large hexagonal crystals (diameter of the hexagonal plane > 7 micrometers ) revealed multiline laser emission, while smaller crystals (diameter about 5 micrometers ) oscillate on one single line. The laser threshold power density decreases with decreasing diameter of the crystals. In terms of pumping needed to reach lasing molecular sieve microlasers are comparable to quantum dot semiconductor lasers.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
