Bloch Surface Waves and Internal Optical Modes-Driven Photonic Crystal-Coupled Emission Platform for Femtomolar Detection of Aluminum Ions

Abstract

The intrinsically lossy nature of plasmonic-based detection platforms necessitates the use of alternative nanophotonic platforms such as one-dimensional photonic crystals (1DPhCs) to exploit properties pertaining to photonic stop band (PSB), Bloch surface waves (BSWs), microcavity, and band-edge modes. We present a highly desirable confinement of internal optical modes (IOMs) and large surface electromagnetic (EM) field due to BSWs on a plasmon-free, metal template-free, photonic crystal-coupled emission (PCCE) platform ensuing 44-fold emission enhancements of the, otherwise, omnidirectionally emitting radiating dipoles. The effect of dielectric thickness in the PCCE platform has also been explored, and the optimized thicknesses for enhanced coupling of both BSWs and IOMs with the radiating dipoles have been obtained. Cavity engineering involving quantum emitters sandwiched in hot spots between 1DPhCs and Ag nanoparticles (AgNPs) has delivered ∼200-fold emission enhancements on account of the improved local density of states (LDOS) via exceptional EM field trapping by BSWs, IOMs, and localized surface plasmon resonance (LSPR) of plasmonic nanoparticles. Experimental results that are in strong agreement with the numerically calculated data validate this augmentation in enhancements due to the amplified coupling between the radiating dipoles and modes supported by 1DPhCs. Moreover, the tightly entrapped optical energy within the hot spots between AgNPs and 1DPhCs was adopted for sensing environmentally hazardous Al 3+ ions at a 0.21 parts per quadrillion (ppq) limit of detection in drinking water samples with reliable and reproducible results, opening new avenues for investigating distinctive photonic crystal nanoarchitectures as a robust, practical, and user-friendly technology for multiplexed diagnostic fluorescence assays.

Cellphone-Aided Attomolar Zinc Ion Detection Using Silkworm Protein-Based Nanointerface Engineering in a Plasmon-Coupled Dequenched Emission Platform

“…The overall characteristic fluorescence emission (radiative decay) is determined by the photonic mode density (PMD) contributed from this interface as well as the competition from other nonfluorescent (nonradiative) pathways. , Hence, maximizing the emission includes two important approaches: (i) enhancing the local electromagnetic (EM) field in the vicinity of fluorophores with additional PMDs and (ii) suppressing the quenching phenomenon . The former has been particularly achieved with the use of different nanomaterials and their hybrid composites. , Needless to say, plasmonic nanomaterials have rendered a paradigm shift in the applications concerning fluorescence with the emergence of plasmon-enhanced fluorescence (PEF) techniques. , This is accomplished by the ability of the localized surface plasmon resonance (LSPR) from plasmonic nanoparticles (NPs) to overcome the size mismatch between the impinging photons and molecules/analytes under study with the generation of the so-called “hotspots” which are nanoregions of high EM field intensity. , Consequently, PEF obtained with different plasmophores (plasmonic NPs in the proximity of fluorophores) has been used in several applications encompassing environmental and human health monitoring, forensics, biosensing, and homeland security. − …”

Plasmon-Coupled Directional Emission from Soluplus-Mediated AgAu Nanoparticles for Attomolar Sensing Using a Smartphone

“…In our case, in RK optical configuration, the emission is expected at angles where minimum reflectivity is expected theoretically, in line with our earlier works. 7,19,35 In this context, we have carried out TFClac simulations to theoretically understand the expected angle of emission and to further correlate them with the experimental values. From Figure 2a,b, we note that a sharp dip in the reflectivity is observed for p-polarized or transverse magnetic component of light.…”

“…Freshly prepared 1 and 2 wt % PVA spin coated at 3000 rpm for 1 min results in 30 and 60 nm thick coatings as reported earlier. 11,35 In the spacer nanointerface, the SPCE substrate (50 nm Ag) was first spin coated with 60 nm PVA doped with NPs of interest. This was followed by spin coating PVA doped with RhB to obtain an overcoat of 30 nm nanolayer containing radiating dipoles.…”

“…The weight (wt) percentage (%) of PVA polymer matrix was varied without altering the spin coating parameters (3000 rpm for 1 min) to obtain different thickness of PVA thin films. Freshly prepared 1 and 2 wt % PVA spin coated at 3000 rpm for 1 min results in 30 and 60 nm thick coatings as reported earlier. , In the spacer nanointerface, the SPCE substrate (50 nm Ag) was first spin coated with 60 nm PVA doped with NPs of interest. This was followed by spin coating PVA doped with RhB to obtain an overcoat of 30 nm nanolayer containing radiating dipoles.…”

Particle swarm optimization of GaAs-AlGaAS nanowire photonic crystals as two-dimensional diffraction gratings for light trapping

“…In particular, thanks to their high symmetry, are excellent platforms to design diffraction gratings able to guarantee the fine control of light coupling along certain directions for specific frequencies, depending on the design parameters The employment of optimised photonic structures to enhance specific optical functionalities is a vibrant research topic. Such a feature is largely exploited for light trapping based applications [4] such as solar cells [5,6] and sensing [7][8][9][10][11], or to control the emission of optical emitters [12][13][14]. In this context, ordered semiconductor nanowire (NW) ensembles grown onto a substrate are a suitable starting platform [15][16][17].…”