Bragg extraction of light in 2D photonic Thue–Morse quasicrystals patterned in active CdSe/CdS nanorod–polymer nanocomposites

Abstract

In this paper two-dimensional (2D) photonic Thue-Morse quasicrystals (ThMo-PQCs) in active CdSe/CdS nanorod (NR) doped polymer nanocomposites are proposed and experimentally demonstrated. Active PQCs and undoped lattices have been prepared in a one-step fabrication process by an electron beam lithography technique (EBL) and the effects on light extraction and emission directionality are studied experimentally. Vertical extraction of light was found to be strongly dependent on both the geometric parameters of the ThMo-PQCs and the presence of NR dopants. By changing the geometrical parameters of the photonic structures, the resonance peak could be tuned from a narrow bluish green emission at 543 nm up to a red-NIR emission at 711 nm with a full width at half-maximum of 22 nm which is in good agreement with Bragg's diffraction theory and free photon band structure. Angular resolved measurements revealed a directional profile in the far-field distribution with guided mode extraction in both doped and undoped PQCs and an enhancement as high as 6.5-fold in light extraction was achieved in the doped photonic structures. These experimental results indicate the critical role of the CdSe/CdS NRs in improving the light extraction efficiency of 2D ThMo-PQCs for solid-state lighting and lasing.

Quantum dot emission modulation using piezoelectric photonic crystal MEMS resonators

“…One method for controlling and enhancing QD emission is to incorporate them into nanostructures, such as nanopillars [14], plasmonic surfaces [15], gratings [16], and photonic crystals (PCs) [17][18][19]. PCs are dielectric nanostructures with periodic variation in their refractive index that can be designed to function as optical resonators at specific wavelengths, with the ability to couple energy into QDs at their excitation wavelength [18,19] and to channel QD emission in specific desired directions from the PC surface [20,21]. PC-enhanced excitation and extraction have been utilized for applications that include biosensing [22] and lighting [5], where increased brightness from photon emitters can be used to reduce limits of detection and to increase signal-to-noise ratios.…”

Region specific enhancement of quantum dot emission using interleaved two-dimensional photonic crystals

“…By varying the duty cycle, period, and refractive index, the resonant characteristics of a PC can be tuned to interact with wavelengths extending from the ultraviolet [5] to the infrared [6,7]. These properties have been used for a variety of applications including polarizers, filters [8], biosensors [9], optical communication components [10], displays, and lighting [11].…”

“…Quantum dots (QDs), semiconductor nanocrystals that down-convert light from a broad band of excitation wavelengths to a very specific emission wavelength [15,16], have been successfully incorporated into PCs with specific resonances designed to couple to the relevant excitation and/or emission wavelengths of the QDs [6,15,[17][18][19][20][21]. By introducing two-dimensional variation into the PC structure, through the use of different periods in orthogonal directions, a PC may incorporate multiple resonances at widely varied wavelengths [3] so as to interact simultaneously with the excitation and emission spectra of the integrated QD emitters [17] as a means of enhancing the number of photons generated by each QD, while increasing the efficiency of emitted photons that reach the viewer.…”

SERS Biosensor Based on Engineered 2D-Aperiodic Nanostructure for In-Situ Detection of Viable Brucella Bacterium in Complex Matrix

“…ThMo aperiodic geometry is generated by the iterative substitution rule: A → AB, B → BA that can be extended to two dimensions [29]. Optical properties of the ThMo nanopattern have been widely investigated and their peculiarities (singular continuous Fourier/Diffraction spectra, self-similar hierarchy of pseudoband-gap regions, omnidirectional reflectivity, and light emission enhancement) make such geometries attractive candidates for the realization of high-performance plasmonic nanosensors [23,[30][31][32][33][34][35][36]. Despite the greater difficulty of both design and fabrication that they require compared to conventional periodical pattern, aperiodic arrangements show important advantages for the realization of sensing systems.…”