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Q: Fachverband Quantenoptik und Photonik
Q 37: Laser applications: Spectroscopy
Q 37.5: Talk
Wednesday, March 20, 2013, 15:00–15:15, F 142
Two-photon excited fluorescence utilizing thermal light — •Andreas Jechow1,2, Henning Kurzke1, Axel Heuer1, Michael Seefeldt1, and Ralf Menzel1 — 1Universität Potsdam, Institut für Physik und Astronomie, Photonik, Karl-Liebknecht-Str. 24-25, Haus 28, 14476 Potsdam — 2Centre for Quantum Dynamics, Griffith University, Brisbane, Australia
Two-photon excited fluorescence (TPEF) is a standard technique in modern microscopy. Due to the low two-photon absorption (TPA) cross section these experiments are typically performed using pulsed laser emission at relatively high intensities, which can lead to photodamage of the probe. Several proposals towards an enhancement of TPA exist including the use of two entangled photons, or biphotons [1].
Here, we utilize thermal light from a fiber-coupled super luminescence diode to demonstrate enhanced TPEF with three common fluorophores that can be used as marker molecules in microscopy. We detected TPEF with powers less than 50 µW and find that the TPA rate for chaotic light is directly proportional to the measured degree of second-order coherence (DSOC), as predicted by theory.
[1] A. Jechow, A. Heuer, and R. Menzel, "High brightness, tunable biphoton source at 976 nm for quantum spectroscopy," Opt. Express 16, 13439-13449 (2008)