Absolute measurement of molecular two-photon absorption cross-sections using a fluorescence saturation technique

Martin Kauert; Martin Frenz; Jaro Rička

doi:10.1117/12.645576

23 February 2006 Absolute measurement of molecular two-photon absorption cross-sections using a fluorescence saturation technique

Martin Kauert, Martin Frenz, Jaro Rička

Author Affiliations +

Proceedings Volume 6089, Multiphoton Microscopy in the Biomedical Sciences VI; 60891S (2006) https://doi.org/10.1117/12.645576
Event: SPIE BiOS, 2006, San Jose, California, United States

Abstract

We demonstrate direct measurements of the absolute molecular two-photon absorption (TPA) cross-sections using a fluorescence technique. A theoretical model of the detected fluorescence signal generated by a femtosecond laser pulse was developed. It is shown that the onset of excited-state saturation depends on the TPA cross-section and the local intensity but is independent of the detection efficiency and the quantum yield. Taking advantage of this, we develop a technique to measure the TPA cross-section that only requires precise knowledge of the space-time profile and the pulse energy of the exciting femtosecond laser beam and of the spatial profile of the observation beam. The exciting beam is generated in the focus of a microscope objective using a hollow core photonic fiber as a spatial filter, whereas the observation is done confocally through a conventional single-mode fiber. An in-house built profiling tool is used for the diagnosis of the tightly focused, highly divergent beams. The method was used with Rhodamine 6G and Rhodamine B dissolved in methanol and excited at 806nm; TPA cross-sections of σ_2R6g=16.0±3.0GM and σ_2RB=17.9±3.0GM, respectively, were measured.

Citation Download Citation

Martin Kauert, Martin Frenz, and Jaro Rička "Absolute measurement of molecular two-photon absorption cross-sections using a fluorescence saturation technique", Proc. SPIE 6089, Multiphoton Microscopy in the Biomedical Sciences VI, 60891S (23 February 2006); https://doi.org/10.1117/12.645576

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available