V. Ciulin

Terahertz electro-optic wavelength conversion in GaAs quantum wells: Improved efficiency and room-temperature operation

A 4-μm-thick sample containing 50 GaAs/AlGaAs asymmetric coupled quantum wells was driven with a strong terahertz (THz) electric field of frequency ωTHz and probed with a near-infrared (NIR) laser of frequency ωNIR. The THz beam modulated the probe to generate sidebands at ωNIR+nωTHz, where n is an integer. Up to 0.2% of the NIR laser power was converted into the n=+1 sideband at 20 K, and sidebands were observed up to room temperature. The strong THz fields also induced changes in the NIR absorption of the sample.

Excitonic Autler-Townes splitting induced by an intense terahertz field

An InGaAs quantum well driven by a strong THz field has exhibited a splitting of the exciton line, due to strong coupling of hole states. This effect is closely-related to the Autler-Townes effect and electromagnetically-induced-transparency.

Terahertz-optical mixing in n-doped GaAs quantum wellso suppression of excitonic resonances

Nonlinear mixing of terahertz and near-infrared radiation is observed for the first time in an n-doped GaAs quantum well. The resonant structure of three-wave mixing is much simpler than in undoped quantum wells

Onset of dynamical localization in a semiconductor superlattic

An excitonic blue-shift is observed when a GaAs/AlGaAs superlattice is irradiated with a strong THz field. This observation is compared with a microscopic calculation, and is consistent with the onset of dynamical localization

Terahertz electrooptic modulation of a single biased GaAs quantum well

We investigate the optical interband properties of GaAs quantum wells driven by a terahertz field. The application of this field shifts the exciton absorption energy. Additionally, terahertz optical sidebands are observed up to 140 K.