Nonlinear photoionization of transparent solids: a nonperturbative theory obeying selection rules

Abstract

We provide a nonperturbative theory for photoionization of transparent solids. By applying a particular steepest-descent method, we derive analytical expressions for the photoionization rate within the two-band structure model, which consistently account for the $selection$ $rules$ related to the parity of the number of absorbed photons ($odd$ or $even$). We demonstrate the crucial role of the interference of the transition amplitudes (saddle-points), which in the semi-classical limit, can be interpreted in terms of interfering quantum trajectories. Keldysh's foundational work of laser physics [Sov. Phys. JETP 20, 1307 (1965)] disregarded this interference, resulting in the violation of $selection$ $rules$. We provide an improved Keldysh photoionization theory and show its excellent agreement with measurements for the frequency dependence of the two-photon absorption and nonlinear refractive index coefficients in dielectrics.

References in corpus (5)

• Impact of the electronic band structure in high-harmonic generation spectra of solids
• Strong-Field Perspective on High-Harmonic Radiation from Bulk Solids
• Band widths and gaps from the Tran-Blaha functional : Comparison with many-body perturbation theory
• Diabatic Mechanisms of Higher-Order Harmonic Generation in Solid-State Materials under High-Intensity Electric Fields
• Mechanism of High-Order Harmonic Generation from Periodic Potentials