Phonon induced phase grating in quantum dot system.

Electromagnetically induced phase grating is theoretically investigated in the driven two-level quantum dot exciton system at the presence of the exciton-phonon interactions. Due to the phonon-induced coherent population oscillation, the dispersion and absorption spectra are sharply changed and the phase modulation is enhanced via the high refractive index with nearly-vanishing absorption, which could effectively diffract a weak probe light into the first-order direction with the help of a standing-wave control field. Moreover, the diffraction efficiency of the grating can be easily manipulated by controlling the Huang-Rhys factor representing the exciton-phonon coupling, the intensity and detuning of the control field, and the detuning of the probe field. The scheme we present has potential applications in the photon devices for optical-switching and optical-imaging in the micro-nano solid-state system.