Acoustically induced Stark effect for excitons in intrinsic semiconductors- art. no. 136403

A Stark effect for excitons parametrically driven by coherent acoustic phon ons is proposed. Our scheme refers to a low-temperature intrinsic semicondu ctor or semiconductor nanostructure pumped by an acoustic wave (frequency b and v(ac) similar or equal to 1-40 GHz and intensity range I-ac similar or equal to 10(-2)- 10(2) W/cm(2)) and probed by low-intensity light. Tunable optical band gaps, which strongly change the spectral shape of the exciton line, are induced in the polariton spectrum by acoustic pumping. We develop an exactly solvable model of the acoustic Stark effect and apply our resul ts to GaAs driven by bulk or surface acoustic waves.