title: Two-photon fluorescence excitation using an integrated optical microcavity: a promising tool for biosensing of natural chromophores.
abstract: Application of an integrated optics (IO) microcavity (MC) for evanescent excitation of two-photon excited fluorescence (TPF) is demonstrated. The MC provides a high local intensity, which is required for the TPF, because of resonant enhancement of the intracavity power and a strong two-dimensional confinement of the guided mode. Numerical estimations show a large increase, by more than a factor of 10(4) of the TPF intensity at the MC compared to a conventional straight waveguide. This will lead to a significant improvement of the detection limits of UV-absorbing chromophores (down to 10(-8)M) when using the MC as a biosensor. Feasibility of TPF excitation using an IO MC is confirmed experimentally for the first time.
authors.affiliation: Biophysical Techniques, Department of Science and Technology, MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Evgueni
authors.initials: E
authors.lastname: Krioukov
authors.forename: Dion
authors.initials: D
authors.lastname: Klunder
authors.forename: Alfred
authors.initials: A
authors.lastname: Driessen
authors.forename: Jan
authors.initials: J
authors.lastname: Greve
authors.forename: Cees
authors.initials: C
authors.lastname: Otto