Transmission in near-infrared optical windows for deep brain imaging

• Published in: Journal of biophotonics Vol. 9; no. 1-2; pp. 38 - 43
• Main Authors: Shi, Lingyan, Sordillo, Laura A., Rodríguez-Contreras, Adrián, Alfano, Robert
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.01.2016; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Animals; Brain; Brain - cytology; deep brain imaging; Detectors; Femtosecond; Fluorescence; golden optical tissue window; Imaging; Infrared Rays; Lasers; near-infrared; Optical Imaging - methods; Optical Phenomena; Rats; Scattering, Radiation; Semiconductors; total attenuation length; transmittance; Wavelengths; total attenuation length; deep brain imaging; near-infrared; transmittance; golden optical tissue window
• ISSN: 1864-063X; 1864-0648
• DOI: 10.1002/jbio.201500192

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. Near‐infrared (NIR) radiation has been employed using one‐ and two‐photon excitation of fluorescence imaging at wavelengths 650–950 nm 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.