Lakowicz Joseph R, Malicka Joanna, Gryczynski Ignacy, Gryczynski Zygmunt
University of Maryland at Baltimore, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, MD 21201, USA.
Biochem Biophys Res Commun. 2003 Aug 1;307(3):435-9. doi: 10.1016/s0006-291x(03)01214-2.
Fluorescence emission is nearly isotropic in space. With typical optical components the collection efficiency is 1% or less. In this preliminary report, we describe a novel approach to transforming the normally isotropic emission into directional emission with a collection efficiency near 50%. This can be accomplished for fluorophores located near a semi-transparent silver film on a glass substrate. The emission couples with the surface plasmon resonance on the silver surface and enters the transparent substrate at a sharply defined angle, the surface plasmon angle for the emission wavelength. We estimate that 40-70% of the total emission enters the substrate at the plasmon angle and can thus be directed towards a detector. Background emission from fluorophores distant from the silver does not couple with the plasmon and is not detected. Different emission wavelengths couple at different angles allowing spectral discrimination without additional optics. Surface plasmon-coupled emission represents a new technology which can be used for high detection efficiency with microfluidic and/or surface-bound assay formats.
荧光发射在空间上几乎是各向同性的。使用典型的光学组件，收集效率为1%或更低。在本初步报告中，我们描述了一种将通常的各向同性发射转换为定向发射的新方法，其收集效率接近50%。对于位于玻璃基板上半透明银膜附近的荧光团，这是可以实现的。发射光与银表面的表面等离子体共振耦合，并以一个明确定义的角度进入透明基板，即发射波长的表面等离子体角度。我们估计，总发射光的40 - 70%以等离子体角度进入基板，因此可以导向探测器。远离银的荧光团的背景发射不与等离子体耦合，不会被检测到。不同的发射波长以不同的角度耦合，无需额外的光学元件即可实现光谱鉴别。表面等离子体耦合发射代表了一种可用于微流体和/或表面结合检测形式的高检测效率的新技术。
