Optofluidics technology based on colloids and their assemblies

Optofluidic technology is believed to provide a breakthrough for the currently underlying problems in microfluidics and photonics/optics by complementary integration of fluidics and photonics. The key aspect of the optofluidics technology is based on the use of fluidics for tuning the optical properties and addressing various functional materials inside of microfluidic channels which have build-in photonic structures. Through the optofluidic integrations, fluidics enhances the controllability and tunability of optical systems. In particular, colloidal dispersion gives novel properties such as photonic band-gaps and enhanced Raman spectrum that conventional optofluidic devices cannot exhibit. In this paper, the state of the art of the colloidal dispersions is reviewed especially for optofluidic applications. From isolated singlet colloidal particles to colloidal clusters, their self-organized assemblies lead to optical manipulation of the photonic/optical properties and responses. Finally, we will discuss the prospects of the integrated optofluidics technology based on colloidal systems.