Coherent acoustic vibrations in silicon submicron spiral arrays

Mechanical properties of complex silicon submicron structures have been studied both experimentally and theoretically using time resolved ultrafast spectroscopy and finite element analysis. Periodic and random arrays of single-turned silicon submircron spirals were grown using the oblique angle deposition technique. Resonant vibrational modes of the submicron spirals were coherently excited by femtosecond laser pulses. Excitation of multiple harmonics of the resonant vibrations has been observed, and the mode patterns of the excited vibrations in the submicron spirals have been calculated.