Stimulated Terahertz Emission from Intraexcitonic Transitions inCu2O

Stimulated terahertz emission from intraexcitonic transitions in Cu2O.

We report the first observation of stimulated emission of terahertz radiation from internal transitions of excitons. The far-infrared electromagnetic response of Cu2O is monitored via broadband terahertz pulses after ultrafast resonant excitation of three-dimensional 3p excitons. Stimulated emission from the 3p to the energetically lower 2s bound level occurs at a photon energy of 6.6 meV, with...

Terahertz Stimulated Emission from Silicon Doped by Hydrogenlike Acceptors

Plasmon Amplification through Stimulated Emission at Terahertz Frequencies in Graphene

We show that plasmons in two-dimensional graphene can have net gain at terahertz frequencies. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers can lead to plasmon amplification through the process of stimulated emission. We show that the net gain values can exceed 10 cm−1 in the 1-10 terahertz frequency range, for electron-hole densities...

Terahertz emission from Ga1−xInxSb

We report an experimental study on terahertz THz emission from Ga1−xInxSb with 0 x 1. THz emission is excited by femtosecond near-infrared laser pulses. For this material system THz emission is maximized for an In mole fraction x 0.5. The maximum in THz emission occurs as a result of carrier compensation NA NB for this specific material composition. The THz emission from n-type InSb is twice as...

Stimulated terahertz emission from group-V donors in silicon under intracenter photoexcitation

Frequency-tunable radiation from the free electron laser FELIX was used to excite neutral phosphorus and bismuth donors embedded in bulk monocrystalline silicon. Lasing at terahertz frequencies has been observed at liquid helium temperature while resonant pumping of odd parity impurity states. The threshold was about two orders of magnitude below the value for photoionization pumping. The influ...