Here, I is the intensity of the respective spectral feature (E11 or E11 * ). To examine single defect reactions on single particles the changes of brightness of single SWCNTs were tracked. For the E11 channel, E11 intensities of single SWCNTs directly decreased (figure ), which resembles the bulk picture (figure ). Afterwards E11 intensities did not change anymore. On the contrary, the E11 * intensities of single SWCNTs showed a diverse behavior (Figure ). These observations are in good agreement with the stochasticity of quantum defects in SWCNTs.