Optical fibers were used to induce fluorescence by means of two-photon
absorption in fluorophores. The effect, studied in a solution of 4',6
-diamidino-2-phenylindole, demonstrated that a single-mode fiber is a
more efficient two-photon excitation source than a multimode fiber. Th
is vas shown with three different fibers. (C) 1995 Optical Society of
America