Terahertz electron-hole recollisions in GaAs/AlGaAs quantum wells: robustness to scattering by optical phonons and thermal fluctuations

摘要

Electron-hole recollisions are induced by resonantly injecting excitons witha near-IR laser at frequency $f_{\text{NIR}}$ into quantum wells driven by a~10 kV/cm field oscillating at $f_{\text{THz}} = 0.57$ THz. At $T=12$ K, up to18 sidebands are observed at frequencies $f_{\text{sideband}}=f_{\text{NIR}}+2nf_{\text{THz}}$, with $-8 \le 2n \le 28$. Electrons and holes recollide withtotal kinetic energies up to 57 meV, well above the $E_{\text{LO}} = 36$ meVthreshold for longitudinal optical (LO) phonon emission. Sidebands with orderup to $2n=22$ persist up to room temperature. A simple model shows that LOphonon scattering suppresses but does not eliminate sidebands associated withkinetic energies above $E_{\text{LO}}$.