Abstract: A method is provided for detecting a fluorescent species that is reversibly photoswitchable at high frequency, and more precisely to a method for detecting at least one reversibly photoswitchable fluorescent species, including a step consisting in illuminating a sample containing a reversibly photoswitchable fluorescent species with a first illuminating light beam, of wavelength ?1, and periodically modulated at an angular frequency ?, and with a second illuminating light beam of wavelength ?2 different from ?1, which is periodically modulated at the angular frequency ?, the second illuminating light beam being modulated in antiphase with respect to the first illuminating light beam.

Abstract: A method is provided for detecting a fluorescent species that is reversibly photoswitchable at high frequency, and more precisely to a method for detecting at least one reversibly photoswitchable fluorescent species, including a step consisting in illuminating a sample containing a reversibly photoswitchable fluorescent species with a first illuminating light beam, of wavelength ?1, and periodically modulated at an angular frequency ?, and with a second illuminating light beam of wavelength ?2 different from ?1, which is periodically modulated at the angular frequency ?, the second illuminating light beam being modulated in antiphase with respect to the first illuminating light beam.

Abstract: A method for detection of at least one reversibly photo-convertible fluorescent species, comprises the following steps: a) illumination of a sample comprising said or at least one of the reversibly photo-convertible fluorescent species by a periodically modulated illuminating light; and b) detection of fluorescent emission emitted by the sample thus illuminated; wherein the method further comprises the following step: c) extraction of the amplitude of the intensity component of the fluorescent emission exhibiting the same periodicity as the periodically modulated illuminating light and a phase quadrature with respect to the same; and wherein the mean intensity of the illuminating light and the modulation frequency of the same are chosen to maximize the amplitude of the intensity component of the fluorescent emission.

Abstract: Method for detection of at least one reversibly photo-convertible fluorescent species (P), comprising the following steps: a) illumination of a sample comprising said or at least one of said reversibly photo-convertible fluorescent species by a periodically modulated illuminating light (FEX); and b) detection of fluorescent emission (FLU) emitted by the sample thus illuminated; characterized in that the method further comprises the following step: c) extraction of the amplitude (IFOUt) of the intensity component of said fluorescent emission exhibiting the same periodicity as said periodically modulated illuminating light and a phase quadrature with respect to the same; and in that the mean intensity of said illuminating light and the modulation frequency of the same are chosen in such a way as to maximise said amplitude of the intensity component of said fluorescent emission.