Figure 1 Credit: M. Fernée, unpublished  Figure 1: An example of
spectral diffusion observed in colloidal quantum dots, where the
diffusion rate is on the 1-second time scale. (Top) This time
series of several hundred spectra from a single quantum dot at
5 K reveals significant variation among individual spectra. (The
bright area indicates the most intense point on the spectrum.)
(Bottom) The average spectrum (blue curve) is significantly
broader than any single spectrum (red curve shows a typical
example), and the peak frequency of each spectrum wanders back
and forth.