Sadegh, SanazYang, Mu-HanFerri, Christopher G. L.Thunemann, MartinSaisan, Payam A.Wei, ZheRodriguez, Erik A.Adams, Stephen R.Kiliç, KivilcimBoas, David A.Sakadžić, SavaDevor, AnnaFainman, Yeshaiahu2020-05-132020-05-132019S. Sadegh, M.H. Yang, C.G.L. Ferri, M. Thunemann, P.A. Saisan, Z. Wei, E.A. Rodriguez, S.R. Adams, K. Kilic, D.A. Boas, S. Sakadzic, A. Devor, Y. Fainman. 2019. "Efficient non-degenerate two-photon excitation for fluorescence microscopy." Opt Express, Volume 27, Issue 20, pp. 28022 - 28035. https://doi.org/10.1364/OE.27.0280221094-4087https://hdl.handle.net/2144/40818Non-degenerate two-photon excitation (ND-TPE) has been explored in two-photon excitation microscopy. However, a systematic study of the efficiency of ND-TPE to guide the selection of fluorophore excitation wavelengths is missing. We measured the relative non-degenerate two-photon absorption cross-section (ND-TPACS) of several commonly used fluorophores (two fluorescent proteins and three small-molecule dyes) and generated 2-dimensional ND-TPACS spectra. We observed that the shape of a ND-TPACS spectrum follows that of the corresponding degenerate two-photon absorption cross-section (D-TPACS) spectrum, but is higher in magnitude. We found that the observed enhancements are higher than theoretical predictions.p. 28022 - 28035en-US© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.Optical physicsCommunications technologiesElectrical and electronic engineeringOpticsArticle10.1364/OE.27.0280220000-0002-6709-7711 (Boas, DA)0000-0002-5143-3960 (Devor, A)489743