Abstract: The disclosure may relate to a method for the characterization of the 3D orientation of an emitting dipole within a specimen. The method comprises splitting a light beam emitted by the emitting dipole and exiting an objective lens into a first and a second beams; spatially filtering said first beam by using a spatial frequency filter; splitting each of said filtered first beam and said second beam into two beams linearly polarized using polarizing beam splitters; detecting with an optical detection unit four beams linearly polarized in a detection plane optically conjugated with the front focal plane of said microscope objective lens; determining, from four intensity images, in a predefined frame of the specimen, the mean orientation and the angular aperture of the distribution of the 3D orientation of the emitting dipole, during an acquisition time of said four intensity images.

Abstract: The present description relates according to a first aspect to a method for measurement of optical properties of at least one particle in a sample (10) and permits, for example, quantitative determination of the complex dipolar polarizability of at least one particle present in a sample. The optical characterization method comprises the illumination of said sample (10) using a light beam, the sample (10) being positioned in the object space of an optical system (120); the acquisition of at least one phase image and at least one intensity image of said at least one particle illuminated by the light beam, the acquisition being carried out in an analysis plane arranged in the image space of the optical system (120); and the determination of at least one optical property of said at least one particle from said at least one phase image and at least one intensity image.