Mechanical modes of an `Alligator' photonic crystal waveguide.

We present our experimental observations on opto-mechanical coupling for guided optical light fields of an `Alligator' photonic crystal waveguide (APCW). Quasi-odd harmonics of the fundamental mechanical mode are observed for optical light frequency in the waveguide regime, while both quasi-odd and quasi-even harmonics are observed for optical light frequency near the band-edge of the APCW. A novel theoretical model of transduction mechanisms is developed to explain the experimental observations.