Beyond the effective mass approximation: predictive theory of the nonlinear optical response of conduction electrons

Abstract

We present an experimental and computational study of the nonlinear optical response of conduction electrons to intense terahertz (THz) electric field. Our observations (saturable absorption and an amplitude-dependent group refractive index) can be understood on the qualitative level as the breakdown of the effective mass approximation. However, a predictive theoretical description of the nonlinearity has been missing. We propose a model based on the semiclassical electron dynamics, a realistic band structure, and the free electron Drude parameters to accurately calculate the experimental observables in InSb. Our results open a path to predictive modeling of the conduction-electron optical nonlinearity in semiconductors, metamaterials, as well as high-field effects in THz plasmonics.

References in corpus (4)

• Impact ionization in InSb probed by THz-pump THz-probe spectroscopy
• THz-pump -- THz-probe spectroscopy of semiconductors at high field strengths
• Non-perturbative Interband Response of InSb Driven Off-resonantly by Few-cycle Electromagnetic Transients
• Self-phase modulation of a single-cycle terahertz pulse by nonlinear free-carrier response in a semiconductor

Cited by in corpus (1)

• 2D THz spectroscopic investigation of ballistic conduction-band electron dynamics in InSb