Abstract

The transient optical property of matters under an intense laser field is the interesting and important subject. The change of the dielectric function under an alternating electric field is known as the dynamical Franz-Keldysh effect (DFKE) [1], which has been illustrated by the blue shift of the band gap. This blue shift corresponds to the AC-Stark shift in atoms and molecules. However, the blue shift of the band gap is the cycle-averaged observable, and the time-evolution of the DFKE in an optical cycle is still unclear. To uncover the physics of the DFKE, we attempt two distinct theoretical approaches, the first-principle calculation and the analytical formalism, taking diamond as the typical insulator.

© 2015 IEEE