文章基本信息

标题：Breaking the diffraction-limited resolution barrier in fiber-optical two-photon fluorescence endoscopy by an azimuthally-polarized beam
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作者：Min Gu ; Hong Kang ; Xiangping Li 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2014
卷号：4
DOI：10.1038/srep03627
出版社：Springer Nature
摘要：Although fiber-optical two-photon endoscopy has been recognized as a potential high-resolution diagnostic and therapeutic procedure in vivo , its resolution is limited by the optical diffraction nature to a few micrometers due to the low numerical aperture of an endoscopic objective. On the other hand, stimulated emission depletion (STED) achieved by a circularly-polarized vortex beam has been used to break the diffraction-limited resolution barrier in a bulky microscope. It has been a challenge to apply the STED principle to a fiber-optical two-photon endoscope as a circular polarization state cannot be maintained due to the birefringence of a fiber. Here, we demonstrate the first fiber-optical STED two-photon endoscope using an azimuthally-polarized beam directly generated from a double-clad fiber. As such, the diffraction-limited resolution barrier of fiber-optical two-photon endoscopy can be broken by a factor of three. Our new accomplishment has paved a robust way for high-resolution in vivo biomedical studies.