Self-assembled organic and polymer photonic crystals for laser applications

This article describes an overview of recent developments in fabrication and uses of self-assembled photonic crystals (PCs) of organic and polymer materials, such as chiral liquid crystals (CLCs) and colloidal crystals (CCs), for laser applications. Both CLCs and CCs have intrinsic capabilities to spontaneously assemble 1D-PC and 3D-PC structures, respectively. When a periodic length in the PC structures of CLCs and CCs corresponds to several hundred nanometers of the light wavelength, the photonic band-gaps (PBGs) can be visualized as Bragg reflection colors. When combining fluorescence dyes in the CLCs and CCs, the stimulated laser action at PBG band edge(s) or within the PBG wavelength can be generated by optical excitation. Moreover, the optically excited laser action is controllable by external stimuli due to the self-organization of CLCs and CCs. This review highlights not only the research backgrounds of CLC and CC structures as PCs, but also the experimental results of their versatile soft and tunable laser applications. We believe that a wide variety of CLC and CC structures will have leading roles in the next generation of optoelectronic devices of organic and polymer materials.