Photonic crystal fibers have been around for a while, but a new wave of research is making them even more interesting. Loading these fibers with gain media of different wavelengths is the name of the game. PC fiber infiltration has been attempted by researchers for a while, but most methods rely on capillary action or gases and vapors. Researchers from University of Sydney in Australia were able to include the potential gain medium into the fiber preform and then pull polymer fibers which contain colloidal quantum dots or rhodamine dye encapsulated into a silica shell. The paper, published in Optics Express, can be found here. This is really exciting, because these kinds of techniques pave the way for a variety of active optical components operating at non-standard wavelengths, which are obviously plug and play with current fiber technology.

  A figure taken from the paper by Yu et.al. [http://www.opticsexpress.org/abstract.cfm?id=140129] shows the photonic crystal fiber polymer preform and filled fibers.