Two-photon excited fluorescence enhancement with broadband versus tunable femtosecond laser pulse excitation

Chao Wang; Alvin T. Yeh

doi:10.1117/1.JBO.17.2.025003

2 March 2012 Two-phoston excited fluorescence enhancement with broadband versus tunable femtosecond laser pulse excitation

Chao Wang, Alvin T. Yeh

Author Affiliations +

Journal of Biomedical Optics, Vol. 17, Issue 2, 025003 (March 2012). https://doi.org/10.1117/1.JBO.17.2.025003

Abstract

The inverse relationship between two-photon excited fluorescence (TPEF) and laser pulse duration suggests that two-photon microscopy (TPM) performance may be improved by decreasing pulse duration. However, for ultrashort pulses of sub-10 femtosecond (fs) in duration, its spectrum contains the effective gain bandwidth of Ti:Sapphire and its central wavelength is no longer tunable. An experimental study was performed to explore this apparent tradeoff between untuned sub-10 fs transform-limited pulse (TLP) and tunable 140 fs pulse for TPEF. Enhancement factors of 1.6, 6.7, and 5.2 are measured for Indo-1, FITC, and TRITC excited by sub-10 fs TLP compared with 140 fs pulse tuned to the two-photon excitation (TPE) maxima at 730 nm, 800 nm, and 840 nm, respectively. Both degenerate (v₁ = v₂) and nondegenerate (v₁ ≠ v₂) mixing of sub-10 fs TLP spectral components result in its broad second-harmonic (SH) power spectrum and high spectral density, which can effectively compensate for the lack of central wavelength tuning and lead to large overlap with dye TPE spectra for TPEF enhancements. These pulse properties were also exploited for demonstrating its potential applications in multicolor imaging with TPM.

Citation Download Citation

Chao Wang and Alvin T. Yeh "Two-phoston excited fluorescence enhancement with broadband versus tunable femtosecond laser pulse excitation," Journal of Biomedical Optics 17(2), 025003 (2 March 2012). https://doi.org/10.1117/1.JBO.17.2.025003

Published: 2 March 2012

ACCESS THE FULL ARTICLE

JOURNAL ARTICLE
9 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY