Third order optical nonlinearity of three dimensional massless Dirac fermions

J. L. Cheng, J. E. Sipe, S. W. Wu

We present analytic expressions for the electronic contributions to the linear conductivity ${\sigma }_{3d}^{(1)}(\omega )$ and the third order optical conductivity ${\sigma }_{3d}^{(3)}({\omega }_1,{\omega }_2,{\omega }_3)$ o…