Statistical evaluation of single nano-object fluorescence

Single nano-objects display strong fluctuations of their fluorescence signals. These random and irreproducible variations must be subject to statistical analysis to provide microscopic information. We review the main evaluation methods used so for by experimentalists in the field of single-molecule spectroscopy: time traces, correlation functions, distributions of "on" and "off" times, higher-order correlations. We compare their advantages and weaknesses from a theoretical point of view, illustrating our main conclusions with simple numerical simulations. We then review experiments on different types of single nano-objects, the phenomena which are observed and the statistical analyses applied to them.