Localized overheating-induced microbubble in optically trapped materials

Microbubbles are found in many physical phenomena, and their generation mechanisms are diverse. In this Letter, we observed the microbubble generation effect in the interaction between highly focused laser light and low-bandgap materials. The mechanism was explained by photon absorption and localized heating, while the bandgap energy of the material was found to play a significant role in the generation of microbubbles. Theoretical calculations and experiments were implemented to verify the proposed mechanism. The mechanism can be used to control or avoid the generation of microbubbles in semiconductor devices and fluidic applications.