Nonlinear THz Pump/THz Probe Spectroscopy of n-doped III–V Semiconductors

By utilizing a terahertz (THz) pump/THz probe spectroscopy, the coherent plasma resonances in n-doped III-V semiconductors are clearly demonstrated through the modulations of reflection. The interaction between energetic electrons and the phonon field on the subpicosecond time scale is verified, and it is shown that this interaction applies for acoustic phonon modes. This study provides a unique method to diagnose the overtones of two transverse acoustic phonon responses of semiconductors in a nonlinear regime, and therefore it will contribute to material fingerprinting.