Spectral narrowing of emission in self-assembled colloidal photonic superlattices

Abstract

We report on the influence of a well-designed passband in the stop band of a suitably engineered self-assembled colloidal photonic crystal superlattice on the steady-state emission properties of infiltrated fluorophores. The photonic superlattice was built by convective self-assembly of slabs of silica spheres of two different sizes. Transmission experiments on the engineered photonic crystal structure show two stop bands with an effective passband in between. The presence of this passband results in a narrow spectral range of increased density of states for photon modes. This shows up as a decrease in the emission suppression (enhancement of the emission) in the narrow effective passband spectral region. These experiments indicate that the threshold for lasing can possibly be lowered by spectrally narrowing the emission of fluorophores infiltrated in suitably engineered self-assembled photonic crystal superlattices, and are therefore important towards the realization of efficient all-optical integrated circuits from functionalized photonic superlattices and heterostructures.

Layer‐by‐Layer Approach to (2+1)D Photonic Crystal Superlattice with Enhanced Crystalline Integrity

“…Considerable efforts have also been made to prepare PC superlattices, which can form controllable resonant states within the forbidden gap by introducing an extended periodicity in PC as in electronic superlattice structures. Generally, a PC superlattice is generated by alternatively repeating at least two PCs, with the lattice parameter being slightly different from each other . The extended periodicity in a PC superlattice introduces folding in the Brillouin zone and induces the formation of a series of minibands and corresponding midgap states within PBG .…”

“…For the fabrication of colloidal PC superlattices, Mittleman and co‐workers adopted the evaporation‐induced convective self‐assembly technique and fabricated a six‐layer ABABAB colloidal PC superlattice with clear AB and BA interfaces, while “A” section consisted of N A = 11 {111} lattice planes of 451 nm spheres and “B” section was N B = 17 {111} planes of 381 nm spheres. By using the same method, Clays and co‐workers prepared superlattice ABAB with different thickness by adjusting the concentration of silica suspension. However, precise control of the thickness of the constituent colloidal PCs and the period of the PC superlattice has been a challenge because of the concentration variation of colloidal suspension during evaporation‐induced convective self‐assembly.…”

Nanocrystalline Si-based metal-oxide-semiconductor photodetectors

“…Since the observation of light emission from nanostructured Si materials, all-Si OEIC has been the goal of many researches [3,[5][6][7]. The photodetectors in OEIC usually have pn or pin junction diode structures or bipolar transistor structure fabricated using standard CMOS technology [8][9][10][11].…”

Mini-band states in graded periodic 1D photonic superstructure

“…These induce low group velocity and high density of states. Furthermore, these researches of narrow bands have been experimentally realized in several superlattices such as optical fiber gratings [14], colloidal photonic superlattices [15,16], and superstructure surface plasmons [17,18]. Several theoretical researches have been carried out for the slow light in the dual-periodic crystals [19,20], which were focused on the EM field enhancement in a particular spatial region.…”