Share Email Print

Proceedings Paper

Non-degenerate 2-photon excitation for fluorescence microscopy in scattering medium (Conference Presentation)
Author(s): Yeshaiahu Fainman; Mu-Han Yang; Maxim Abashin; Payam Saisan; Peifang Tian; Christopher Ferri; Anna Devor

Paper Abstract

Non-degenerate 2-photon excitation of a fluorophore with two laser beams of different photon energies may offer independent degree of freedom in tuning of the photon flux (i.e., the power) for each beam. Wereport a practical demonstration that the emission intensity of a fluorophore excited in the non-degenerate regime in scattering medium is more efficient than the commonly used degenerate 2-photon excitation. In our experiments we use spatially and temporally aligned Ti:Sapphiremode-locked laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, respectively. The non-degenerate 2-photon excitation mechanism takes advantage of the infrared wavelengths used in 3-photon microscopy to achieve increased penetration depth, while preserving relatively high 2-photon excitation cross section, exceeding that achievable with the 3-photon excitation. Importantly, independent control of power for each beam implies that the flux requirement for the higher photon energy NIR beam, which experiences higher scattering in biological tissue, can be relaxed at the expense of increasing the flux of the lower photon energy SWIR beam which experiences lower scattering, thus promising deeper penetration with higher efficiency of excitation.Applications for in vivo brain imaging will be also discussed.

Paper Details

Date Published: 2 November 2016
PDF: 1 pages
Proc. SPIE 9956, Ultrafast Nonlinear Imaging and Spectroscopy IV, 995615 (2 November 2016); doi: 10.1117/12.2238599
Show Author Affiliations
Yeshaiahu Fainman, Univ. of California, San Diego (United States)
Mu-Han Yang, Univ. California, San Diego (United States)
Maxim Abashin, National Institute of Standards and Technology (United States)
Univ. of California, San Diego (United States)
Payam Saisan, Univ. of California, San Diego (United States)
HRL Labs., LLC (United States)
Peifang Tian, Univ. of California, San Diego (United States)
John Carroll Univ. (United States)
Christopher Ferri, Univ. of California, San Diego (United States)
Univ. of California, Merced (United States)
Anna Devor, Univ. of California, San Diego (United States)

Published in SPIE Proceedings Vol. 9956:
Ultrafast Nonlinear Imaging and Spectroscopy IV
Zhiwen Liu, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?