M. D. Huang

Controllable switching behavior of defect modes in one-dimensional heterostructure photonic crystals

A dimerlike-positional-correlation heterostructure is used in one-dimensional photonic crystals to introduce the defect mode with perfect transmittance. The switching behavior of the transmittance, at the defect mode, is demonstrated theoretically. When the normal incident beam is tilted at a negligibly small angle, the perfect transmittance peak vanishes. It is found that this condition causing this phenomenon can be easily met and controlled through elucidation on the mechanism. This finding is significant for potential applications in high-precision filters and optical switches.

Fabrication and analysis of one-dimensional defect-induced ultrawide photonic band gaps

An approach named the defect-induced extension of photonic band gaps (PBGs) is proposed, in which a stratified periodic structure is combined with another stratified structure containing defect layers. For comparison, three structures composed of TiO2 and SiO2 alternating layers, perfect, five-defect and combined-photonic crystals (PCs), were fabricated by using an electron-beam evaporation system. The measured PBG width of combined-PCs extended to 370 nm at the normal incidence, nearly three times more than that of perfect ones, 130 nm, but a few ripples are observed within the PBG. In order to elucidate the origin of the ripples, the influence of the refractive-index contrast on the reflectance was analyzed theoretically. When the refractive-index contrast nH∕nL≥1.7, the ripples are eliminated. More importantly, an overdoubled omnidirectional PBG is realized at nH∕nL=2.56, covering the visible region completely. This approach is considered to be based on the light localization and a heterostructure resu...

Influence of array on the transmittance of 1-D magnetic photonic crystals

This work concerns the influence of layer array on the transmittance of 1-D MPCs, consisting of dielectric Al2O3 and magnetic Bi: YIG layers. Bi: YIG is an ideal candidate for MPCs in the visible and the far-IR ranges, where it experiences little absorption. Since the optical constants of Bi:YIG at lambda = 720 nm is well known, we have investigated the properties in a wavelength region centered at this wavelength.