US 5,943,129 AGranted

Fluorescence imaging system

AssigneeCambridge Research & Instrumentation, Inc.

InventorsClifford C. Hoyt, Peter J. Miller

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Abstract

A fluorescence imaging system for epi-illumination wherein the usual dichroic beamsplitter is replaced by a polarizing beamsplitter (PBS). The sample is excited with light that is linearly polarized to a significant degree, and fluorescent emission light is collected in the orthogonal linear polarization state. Excitation light that is scattered or reflected by the sample is rejected by the PBS, while the desired emission light is captured for imaging by a detector. By eliminating the usual dichroic beamsplitter member, the imaging system removes the barriers to multi-spectral imaging that such members conventionally impose. A wavelength-selective birefringent network may also be interposed between the beamsplitter and the sample for converting the polarization of either the excitation or the emission light to the orthogonal state without defeating this desirable rejection property, thus permitting measurement of the sample emissions in either or both linear polarization states for assessing fluorescence polarization.

Claims28

Dependent claims

A fluorescence imaging system for imaging radiation emitted by a sample to be imaged by the system through fluorescing of the sample in response to illumination of the sample by illuminating radiation, said system comprising:

an illumination source operable for emitting a beam of optical illuminating radiation along a first optical path;
a detector for receiving and imaging radiation emitted from a sample along a second optical path in response to illumination of the sample by the illuminating radiation;
a polarizing beamsplitter for (1) receiving illuminating radiation from the illumination source along the first optical path and selectively redirecting only the illuminating radiation of a first polarization state to the second optical path for illuminating the sample with the redirected illumination radiation of the first polarization state so as to effect fluorescing of the sample and emission of radiation from the sample, and for (2) receiving emission radiation from the sample along the second optical path and selectively transmitting through the beamsplitter along the second optical path for receipt by said detector only the emission radiation from the sample having substantially a second polarization state orthogonal to the first polarization state;
and,
at least one additional polarizer disposed in at least one of the first and second optical paths, which preferentially reduces the proportion of excitation light incident upon the detector.

2 more elements

Dependencies are inferred from the claim text.