Opt Lett

Compared with visible light (380-700 nm), near-infrared light (700-1400 nm) undergoes weaker optical attenuation in biological tissue; thus, it can penetrate deeper. Herein, we demonstrate near-infrared optical-resolution photoacoustic microscopy (NIR-OR-PAM) with 1046 nm illumination. A penetration depth of 3.2 mm was achieved in chicken breast tissue ex vivo using optical fluence within the American National Standards Institute (ANSI) limit (100\ue2\u20ac\u2030\ue2\u20ac\u2030mJ/cm2). Beyond \ue2\u2c6\ubc0.6\ue2\u20ac\u2030\ue2\u20ac\u2030mm deep in chicken breast tissue, NIR-OR-PAM has shown finer resolution than the visible counterpart with 570 nm illumination. The deep imaging capability of NIR-OR-PAM was validated in both a mouse ear and a mouse brain. NIR-OR-PAM of possible lipid contrast was explored as well.DP1 EB016986/DP/NCCDPHP CDC HHS/United StatesDP1 EB016986/EB/NIBIB NIH HHS/United StatesR01 CA159959/CA/NCI NIH HHS/United StatesR01 CA159959/CA/NCI NIH HHS/United StatesR01 CA186567/CA/NCI NIH HHS/United StatesR01 CA186567/CA/NCI NIH HHS/United States2014-09-11T00:00:00Z25166107PMC416167