title: Transmission in near-infrared optical windows for deep brain imaging.
abstract: Near-infrared (NIR) radiation has been employed using one- and two-photon excitation of fluorescence imaging at wavelengths 650-950 nm (optical window I) for deep brain imaging; however, longer wavelengths in NIR have been overlooked due to a lack of suitable NIR-low band gap semiconductor imaging detectors and/or femtosecond laser sources. This research introduces three new optical windows in NIR and demonstrates their potential for deep brain tissue imaging. The transmittances are measured in rat brain tissue in the second (II, 1,100-1,350 nm), third (III, 1,600-1,870 nm), and fourth (IV, centered at 2,200 nm) NIR optical tissue windows. The relationship between transmission and tissue thickness is measured and compared with the theory. Due to a reduction in scattering and minimal absorption, window III is shown to be the best for deep brain imaging, and windows II and IV show similar but better potential for deep imaging than window I.
authors.affiliation: Institute for Ultrafast Spectroscopy and Lasers, Department of Physics, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA. lshi365@gmail.com.|Department of Biology, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA. lshi365@gmail.com.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Shi
authors.affiliation: Institute for Ultrafast Spectroscopy and Lasers, Department of Physics, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Sordillo
authors.affiliation: Institute for Ultrafast Spectroscopy and Lasers, Department of Physics, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA.|Department of Biology, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA.
authors.forename: Adrián
authors.initials: A
authors.lastname: Rodríguez-Contreras
authors.affiliation: Institute for Ultrafast Spectroscopy and Lasers, Department of Physics, the City College of the City University of New York, 160 Convent Avenue, New York, NY 10031, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Alfano
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology*; D007259:Infrared Rays; D061848:Optical Imaging / Q000379:methods*; D055620:Optical Phenomena; D051381:Rats; D012542:Scattering, Radiation
keywords: deep brain imaging; golden optical tissue window; near-infrared; total attenuation length; transmittance