How glass responses to laser excitation

Glass is a disordered solid that processes distinct dynamical and elastic properties compared with crystal. Elastically, how heterogeneous a glassy materials can be and to what extend such heterogeneity is determined by structure are long standing puzzles in glass science. In this experiment, we probed the responses of binary colloidal glasses towards the local excitations caused by laser pulses. We observed very similar excitation patterns when the laser was repeated in linear region; directly proving that the dynamical heterogeneity is strongly encoded with structure. In non-linear region, we discovered for the first time a non-monotonic dynamical length scale as a function of $\phi$, resulting from the intriguing interplay between cooperative motion and local structure. Our results highlight the crucial role structure plays in the dynamics and elasticity of glasses.