Modulation of Three Dimensional Photonic Band Gap in Visible Region

Abstract

Three dimensional (3D) SiO2 photonic crystals films were fabricated on quartz substrate by vertical deposition method. The effects of various preparation parameters on optical properties were studied by optical transmission measurements. Bragg reflection on parallel sets of (111) planes were observed in all the samples. The center wavelength of [111] photonic band gap (PBG) varied from 450 nm to 680 nm with the increasing sphere size. For a given sphere size, the (111) Bragg reflection of as-deposited sample shifted towards lower wavelengths as the sintering temperature T increased. The role of evaporation temperature on the optical properties of the film was also investigated. The PBG can be correspondingly modulated in visible region by changing various preparation parameters.

Photonic crystal with magnified resonant peak for biosensing applications

“…However, sensitivity in nm/RIU records an unexpected decrease at a sample layer thickness of 1650 nm because the resonant peak of n s = 1.59 is very close to the right edge of the PBG. This decrease is due to the further away from the center of the PBG, the less sensitivity [57]. Besides, a new resonant peak appears coming from the left side (Supplementary Data: S2).…”

“…Then, at a sample layer thickness of 1500 nm, sensitivity in %/RIU rapidly increases to 5132.1%/RIU before rapidly decreasing. The rapid increase in sensitivity in %/RIU is because the resonant peak at a sample layer thickness of 1500 nm is located very close to the center of the PBG (Supplementary Data: S3), where the transmittance of the resonant peak has the maximum value at the center of the PBG [57]. For FWHM, it dramatically changes between 0.05 nm to 0.6 nm with changing the sample layer thickness from 1000 nm to 2000 nm depending on the transmittance of the resonant peaks (Supplementary Data: S2), as clear in figure 4(C).…”