Acoustic Wannier-Stark ladders and Bloch oscillations in porous silicon structures

摘要

We report the experimental observation of the Wannier-Stark ladders and the Bloch oscillations for acoustic waves in porous silicon structures. We designed and fabricated a structure with an acoustic band gap centered around 1 GHz. We introduced a linear gradient in the acoustical parameter η = 1/v_L~2 to obtain an acoustical Wannier-Stark ladder and we observed it from the transmission measurements. The observed behavior is in excellent agreement with transfer matrix calculations.