Self-phase modulation of a single-cycle terahertz pulse by nonlinear free-carrier response in a semiconductor

Abstract

We demonstrate the self-phase modulation (SPM) of a single-cycle THz pulse in a semiconductor, using bulk n-GaAs as a model system. The SPM arises from the heating of free electrons in the electric field of the THz pulse, leading to an ultrafast reduction of the plasma frequency, and hence to a strong modification of the THz-range dielectric function of the material. THz SPM is observed directly in the time domain. In the frequency domain it corresponds to a strong frequency-dependent refractive index nonlinearity of n-GaAs, found to be both positive and negative within the broad THz pulse spectrum, with the zero-crossing point defined by the electron momentum relaxation rate. We also observed the nonlinear spectral broadening and compression of the THz pulse.

5 pages, 6 figures

References in corpus (3)

• Impact ionization in InSb probed by THz-pump THz-probe spectroscopy
• THz-pump -- THz-probe spectroscopy of semiconductors at high field strengths
• Semiconductor saturable absorbers for ultrafast THz signals

Cited by in corpus (13)

• Microscopic origin of the Drude-Smith model
• High-harmonic generation from an epsilon-near-zero material
• Post-2000 Nonlinear Optical Materials and Measurements: Data Tables and Best Practices
• High Kerr nonlinearity of water in THz spectral range
• Giant self-induced transparency of intense few-cycle terahertz pulses in n-doped silicon
• Nonlinear Transfer of Intense Few Cycle Terahertz Pulse Through Opaque n-doped Si
• Scaling laws for nonlinear electromagnetic responses of Dirac fermions
• Beyond the effective mass approximation: predictive theory of the nonlinear optical response of conduction electrons
• Controlling the water nonlinear refractive index in the THz frequency range via temperature variation
• Front-induced transitions control THz waves
• Roles of band gap and Kane electronic dispersion in the THz-frequency nonlinear optical response in HgCdTe
• Strong-Field Terahertz Control of Plasmon Induced Opacity in Photoexcited Metamaterial
• The Drude-Smith Model for Conductivity: de novo Derivation and Interpretation