Colloidal crystals self-assembled on the end face of fiber: Fabrication and characterizations

We report the experimental demonstration of colloidal crystal deposited on the end face of fiber. Wet chemical etching technique was employed to fabricate a cavity in one side of the fiber while keeping the coating intact. The fiber with cavity was immersed in the PMMA colloidal dispersions and self-assembled colloidal crystal formed in the bottom of the cavity. The resulted sample was characterized structurally by emission scanning electronic microscope (SEM) and optically by transmission spectra analyzer. A moderately transmission dip of ∼4 dB at ∼1542 nm wavelength coincides with the photonic band gap expected for the 690 nm PMMA microspheres. The theoretical calculation agrees very well with the experimental results.