5 research outputs found
Electrically injected cavity polaritons
We have realised a semiconductor quantum structure that produces
electroluminescence while operating in the light-matter strong coupling regime.
The mid-infrared light emitting device is composed of a quantum cascade
structure embedded in a planar microcavity, based on the GaAs/AlGaAs material
system. At zero bias, the structure is characterised using reflectivity
measurements which show, up to room temperature, a wide polariton anticrossing
between an intersubband transition and the resonant cavity photon mode. Under
electrical injection the spectral features of the emitted light change
drastically, as electrons are resonantly injected in a reduced part of the
polariton branches. Our experiment demonstrates that electrons can be
selectively injected into polariton states up to room temperature.Comment: 10 pages, 4 figure
Direct surface cyclotron resonance terahertz emission from a quantum cascade structure
A strong magnetic field applied along the growth direction of a semiconductor
quantum well gives rise to a spectrum of discrete energy states, the Landau
levels. By combining quantum engineering of a quantum cascade structure with a
static magnetic field, we can selectively inject electrons into the excited
Landau level of a quantum well and realize a tunable surface emitting device
based on cyclotron emission. By applying the appropriate magnetic field between
0 and 12 T, we demonstrate emission from a single device over a wide range of
frequencies (1-2 THz and 3-5 THz)
Stabilization and mode-locking of terahertz quantum cascade lasers
reserved14M. Ravaro; P. Gellie; G. Santarelli; C. Manquest; P. Filloux; P.; C. Sirtori; J. Lampin; G. Ferrari; S. Khanna; E. Linfield; H. Beere; D. Ritchie; S. BarbieriM., Ravaro; P., Gellie; G., Santarelli; C., Manquest; P., Filloux; C., Sirtori; J., Lampin; Ferrari, Giorgio; S., Khanna; E., Linfield; H., Beere; D., Ritchie; S., Barbier
Coherent sampling of active mode-locked terahertz quantum cascade lasers and frequency synthesis
International audienceTerahertz quantum cascade lasers are compact, electrically pumped semiconductor laser sources that are capable of delivering tens of milliwatts of power in continuous wave. Here, we demonstrate that these devices can be operated in a regime of active mode-locking by modulating their bias current with a radiofrequency synthesizer. Detection of the emitted pulse train is made possible by phase-locking the quantum cascade laser repetition rate and carrier frequency to a harmonic of the repetition rate of a mode-locked femtosecond fibre laser. This technique allows coherent sampling of the terahertz electric field, showing that the terahertz pulses are transform-limited. In addition, our technique allows control of the carrier-envelope phase shift of the quantum cascade laser