Observation of a stacking process of microparticles with multiple beams.

We developed a method of constructing a stacked structure of microparticles by using multiple beams emitted by a vertical-cavity surface-emitting laser array [Appl. Phys. Lett. 82, 2969 (2003)]. We construct a new observation system to observe the stacked structure and to clarify the stacking process. Results confirmed that the stacked structure was lifted up from the sample stage and fabricated without space between the microparticles. Furthermore, we investigated the difference of stacking processes when 2 x 2 beams and a single beam were used. As a result, we found that a stacked structure, when 2 x 2 beams were used, can be fabricated with lower optical power than when a single beam was used.