Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths

Norris, G and Amor, R and Dempster, J and Amos, W B and McConnell, G (2012) Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths. Journal of Microscopy, 248 (2). pp. 200-207. ISSN 0022-2720

Full text not available in this repository.Request a copy from the Strathclyde author

Abstract

We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620-636 nm, ~150 mW, 405 fs, 80 MHz, M(2) ~ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less.