Fibre-optic two-photon fluorescence microscopy

Centre for Micro-Photonics, Swinburne University of Technology

3.30pm, Friday 4 October 2002, Seminar Room (AR103), Graduate Research Centre, Swinburne

Optical fibres and fibre-optic components are common additions to conventional microscopic imaging systems that make instruments of a more compact and economically viable nature. In biophotonics they enable access to specimens that would be otherwise inaccessible. However, incorporation of such components with multiphoton systems leads to physical difficulties, since in this situation high peak power ultrashort pulses are employed.

In this report the characterisation of properties pertinent to the propagation of high peak power ultrashort pulses through a single-mode optical fibre for two-photon excitation is presented. Both linear and nonlinear effects are considered. Temporal pulse broadening of a significant magnitude arises through linear dispersion and nonlinear effects within the fibre core, which causes a reduction in the high peak power required for two-photon excitation. However, a corresponding broadening of the pulse spectrum over its initial width also occurs which has been shown to lead to an improvement in image resolution. A practical instrument has been developed and is discussed in terms of its ability to obtain high-resolution three-dimensional images.

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