| abstract |
A method of fluorescence measurement on analytes, marked with different fluorescent markers, which have spectrally different fluorescence emissions, in a sample is described, having the following steps: illumination of the sample in the measurement volume using a laser to excite the fluorescence emission of the at least two fluorescent markers, the illumination of the measurement volume being performed with a maximum of one single laser line, having an excitation intensity sufficiently high that the fluorescent markers are jointly excited through 2-photon absorptions, detection of the fluorescence emission using at least two detector devices which are designed for light detection in different spectral ranges in accordance with the spectral fluorescence properties of the fluorescent markers, and performance of a cross-correlation and/or coincidence analysis of detector signals of the detector devices. A measurement device for performing the method is also described. |