ZnO nanorods for efficient third harmonic UV generation: erratum

We correct Eq. (1) of our previous paper showing the pulse\ud duration (τ) dependence on group delay dispersion (β2) and initial duration of the unchirped pulse coming from the laser (τ0). The correct form of the equation was used in all the calculations in the previous paper however, so in all other respects our previous results and conclusions are unchanged