Jeudi 16 octobre
Résumé : In recent years THz semiconductor lasers have known a real resurgence
thanks to the extension of the quantum cascade (QC) concept into the far infrared.
This semiconductor technology is now an attractive choice for the fabrication of
THz lasers for spectroscopic applications and local oscillators for THz heterodyne
detection. These lasers emit several tens of mW in the whole range from 1 to 5 THz,
at cryogenic temperature. Wavelength stabilisation, plasmonic photonic crystals,
beam shaping and impedance match engineering have also been demonstrated.
To speed up the exploitation of THz QC lasers we have been investigating the
possibility of merging these devices with very well established technologies such as
microwaves and telecommunications. By “hybridising” THz techniques with these
mature technologies we are favouring new ideas for system applications and at the
same time help to move forward research in the THz frequency range. In this
context we have also used THz time domain spectroscopy (TDS) to investigate key
parameters such as the spectral gain and losses of THz QCLs. This technique allows
us to measure the amplitude and phase of the stimulated emission.
Finally I will present our results of electroluminescence from cavity polaritons and
the experimental observation of strong light-matter interaction at THz frequencies,
achieved using a subwavelength photonic confinement. In this case the measured
Rabi splitting is a large fraction, 25%, of the intersubband transition.
RECRUTEMENT ACCES DIRECT
Le département de physique
Fête de la Science 2018 