Abstract
Two different optical methods for the determination of particle size distributions in the nanometer range are described. One method uses the scattering of polarized light at different angles and applies a regularized inversion algorithm and is applicable for arbitrary materials. In the other method, light-absorbing particles are heated by a short laser pulse up to evaporation temperature, and the temperature of the particles is determined by the measurement of the thermal radiation. This method has been applied since many years; the detailed analysis, however, shows that one has to be careful with interpretation of the measured data.
