Fabrication of one-dimensional alumina photonic crystals with a narrow band gap and their application to high-sensitivity sensors

In this study, alumina photonic crystals (PCs) were fabricated by applying a sine-wave current in the anodization of aluminum. The effect of periodic time and peak–peak value of the current on the photonic band gap (PBG) were discussed. By selecting the appropriate experimental conditions, a full-width at half maximum (FWHM) of the PBG of only 18 nm was achieved. The experimental results show that the central position of the PBG was proportional to the periodic time of the current signal in the anodization process. A short periodic time allowed the formation of alumina PCs with a narrow band gap. By changing the peak–peak value of the current, the position of the PBG with a narrow FWHM could also be tuned artificially. The as-prepared alumina PCs showed a linear shift of PBG position and transmittance with the increase of refractive index of the analytes infiltrated into the pores, indicating their potential application in chemical sensing or bio-sensing.