The present disclosure relates to the field characterization of particles in a sample solution. More specifically, the present disclosure relates to a flow cell and a method for characterizing particles by means of collected non-Gaussian temporal signals. The present flow cell and method rely on an excitation fiber with a channel. The excitation fiber has a core for transporting an excitation light generated by a light source, and defines a channel through a portion of its core. The channel of the excitation fiber directs a flow of the sample solution. The excitation fiber, the channel and collection fibers characteristics are selected, proportioned and positioned to generate collected light with a non-Gaussian temporal intensity profile.