Resonant light delay in GaN with ballistic and diffusive propagation.
We report on a strong delay in light propagation through bulk GaN, detected by time-of-flight spectroscopy. The delay increases resonantly as the photon energy approaches the energy of a neutral-donor bound exciton (BX), resulting in a velocity of light as low as 2100 km/s. In the close vicinity of the BX resonance, the transmitted light contains both ballistic and diffusive components. This phenomenon is quantitatively explained in terms of optical dispersion in a medium where resonant light scattering by the BX resonance takes place in addition to the polariton propagation.
Shubina
T V
TV
Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia.
Glazov
M M
MM
Toropov
A A
AA
Gippius
N A
NA
Vasson
A
A
Leymarie
J
J
Kavokin
A
A
Usui
A
A
Bergman
J P
JP
Pozina
G
G
Monemar
B
B