Micro-dynamics

Non-equilibrium and non-linear behavior of nano-structured materials is studied via micro-ballistics and laser-induced acoustic waves. Our micro-ballistic method, LIPIT, provides unprecedented characterization capabilities for nano-scale dynamic responses.

In the typical LIPIT, a single micro-bullet (~3.7 um diameter) is accelerated to a supersonic speed (<3km/s) by using laser ablation. The kinetic information of the micro-bullet is acquired via high speed photography (~trillion frame per second) using femtosecond laser pulses. We can aim at a specific region of a sample with a high accuracy (only 1.1 deg deflection as shown in the header image above). Because the kinetic energy of the micro-bullet (~ 20 nJ) is 100 billion times smaller than that of a typical rifle bullet (~ 2 kJ), super-high-resolution kinetic information (less than 1 nJ) is possible.

We are not limited to using the micro-ballistic method for the dynamic mechanical characterization at the nano-scale. By using a hollow micro-bullet containing various functional substances such as quantum dots, organic dye, and DNA, this method is drastically being extended beyond mechanics.