Optical necklace states in Anderson localized 1D systems

Abstract

We report on the observation of nonlocalized modes or necklace states of light waves in disordered systems in the Anderson localized regime. The samples consist of positional-disordered binary multilayer systems. Anderson localized modes manifest themselves as narrow high-transmission peaks in the transmission spectrum, whereas the average of the logarithm of the transmission coefficient decreases linearly with thickness. Optical necklace states are observed as modes with a characteristic multiresonance time response and relatively fast decay time.

Light Transmission Properties and Shannon Index in One-Dimensional Photonic Media With Disorder Introduced by Permuting the Refractive Index Layers

“…Instead, for the structures studied in our analysis, the transmission spectrum is affected by disorder in the entire spectral region investigated, including the photonic band region, and is more similar to the one showed in Ref. [26]. We found that introducing disorder produces a significant increase in the average light transmission compared to the ideal photonic crystal below a certain length of the sample.…”

“…Although widely used in applications such as random lasers [22], [23], recent observations (e.g., photon Levy flights [24], disorder enhanced light transport [25]) pay testament to the great effort underway to better understand the singular features of these photonic materials. Anderson localization has been experimentally demonstrated in one-dimensional random photonic structures, showing a narrow peak in the transmission spectrum and an average of the transmission coefficient logarithm which decreases linearly with the sample thickness [4], [26]. Furthermore, optical necklace states have been observed [26], as theoretically predicted by Pendry [27] and Tartakovskii [28].…”

“…Anderson localization has been experimentally demonstrated in one-dimensional random photonic structures, showing a narrow peak in the transmission spectrum and an average of the transmission coefficient logarithm which decreases linearly with the sample thickness [4], [26]. Furthermore, optical necklace states have been observed [26], as theoretically predicted by Pendry [27] and Tartakovskii [28].…”

“…In the first structure the refractive indices of the two materials are n HI1 ¼ 1:69 and n LO1 ¼ 1:6, chosen in order to obtain a low refractive index contrast. In the second structure, inspired by the work of Bertolotti et al [26], the parameters were chosen such that 4d HI2 n HI2 ¼ 4d LO2 n LO2 ¼ 1500 nm using n HI2 ¼ 2:13 and n LO2 ¼ 1:46 as refractive indices of the two materials and d HI2 ¼ 176 nm and d LO2 ¼ 258:6 nm as their thicknesses. For both structures we have considered three sizes of the crystal unit cell: a unit cell composed of a layer of high refractive index material and a layer of low refractive index material (henceforth labeled 2), a unit cell composed of a layer of high refractive index material and two layers of low refractive index material (3) and a unit cell composed of a layer of high refractive index material and three layers of low refractive index material (4).…”

Silicon Nanocrystals in Porous Silicon and Applications

“…Characteristic high transmission peaks due to resonances inside the sample were observed and the localization length was determined. Such random system was used to observe optical necklace states in Anderson localized 1D systems [177].…”