Blue-shifting of coherent plasmon radiation due to Landau damping
Restricting the wave vector of coherent plasmons excited by ultrashort laser pulses results in a frequency blue-shift of the emitted THz radiation, consistent with the onset of Landau damping.
Coherent plasmons in InSb
We study coherent plasmons in the narrow-gap semiconductor InSb by measuring the far-infrared electromagnetic radiation they emit. These collective oscillations are excited with ultrashort, near-infrared laser pulses having photon energy far above the semiconductor band gap. Coherent plasmon behavior is characterized as a function of temperature, doping density, optically injected carrier density, and spatial confinement.
Emission of electromagnetic radiation by coherent vibrational wavesin stimulated Raman scattering
Electromagnetic radiation is emitted by the vibrational and collective modes of an opaque solid as the result of impulsive stimulated Raman scattering. Raman scattering of near-infrared femtosecond laser pulses produces coherent longitudinal optical phonon and plasmon oscillations in the semiconductor InSb. These oscillations radiate into free space at THz frequencies and are directly detected. The THz spectra exhibit features consistent with Raman selection rules including interference of allowed and forbidden Raman scattering.