Guided Bloch Surface Waves on Ultrathin Polymeric Ridges (original) (raw)
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Near-field probing of Bloch surface waves in a dielectric multilayer using photonic force microscopy
Journal of the Optical Society of America B, 2016
The potential of photonic force microscopy (PFM) for probing the optical near-field in the vicinity of a dielectric multilayer is demonstrated. An experimental study of Bloch surface waves (BSWs) using PFM is described in detail. The applied technique is based on measuring the BSW-induced gradient force acting on a probe particle combined with precise control of the distance between the particle and the multilayer surface. The BSW-induced potential profile measured using PFM is presented. The force interaction between the probe and the BSW evanescent field is numerically studied. The results indicate that a polystyrene particle with a diameter of 1 μm does not significantly perturb the BSW field and can be used to probe the optical near-field intensity in an elegant, noninvasive manner.
Journal of The Optical Society of America B-optical Physics, 2010
In this work, we use a multi-heterodyne scanning near-field optical microscope to investigate the polarization and propagation of Bloch surface waves in an ultrathin ͑ϳ /10͒ ridge waveguide. First, we show that the structure sustains three surface modes, and demonstrate selective excitation of each. Then, by numerically processing the experimental data, we retrieve the transverse and longitudinal components of each of the modes, in good agreement with the calculated fields. Finally, we provide an experimental estimation of the effective indices and the dispersion relations of the modes.
Multilayer coatings for Bloch surface wave optical biosensors
Surface and Coatings Technology, 2017
Sensors using surface plasmon resonance (SPR) are established as the method of choice in label-free optical biosensing. Their sensitivity for small refractive index changes at the surface originates from the enhanced evanescent field at the surface of a thin metal layer. However, the small number of well-suited metals (Ag, Au) with fixed optical constants limits a further refinement of the SPR performance in terms of dispersion and resonance width. An alternative can be found in Bloch Surface Waves (BSW) sustained at specially designed dielectric multilayer stacks with low absorption losses. Due to the low losses an enormous narrowing of the resonance is obtained, promising the reduction of the detection limit for such a label-free sensor. Furthermore, fluorescence enhancement caused by near field effects can also be exploited and, by engineering the BSW dispersion, both detection schemes can be combined. This paper illustrates the basic principles of BSW generation by designing thin dielectric multilayer stacks and the vacuum deposition of these coatings on disposable polymer biochips. In addition, the measurement and analysis of the Bloch resonance shift caused by the interaction of biomolecules at extremely small concentrations is presented.
Bloch surface waves confined in one dimension with a single polymeric nanofibre
Nature communications, 2017
Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor-memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes.
Diffraction-Free Bloch Surface Waves
ACS nano, 2017
Here, we demonstrate a diffraction-free Bloch surface wave sustained on all-dielectric multilayers that does not diffract after being passed through three obstacles or across a single mode fiber. It can propagate in a straight line for distances longer than 110 μm at a wavelength of 633 nm and could be applied as an in-plane optical virtual probe both in air and in an aqueous environment. Its ability to be used in water, its long diffraction-free distance, and its tolerance to multiple obstacles make this wave ideal for certain applications in areas such as the biological sciences, where many measurements are made on glass surfaces or for which an aqueous environment is required, and for high-speed interconnections between chips, where low loss is necessary.
Manipulating Bloch surface waves in 2D: a platform concept-based flat lens
Light: Science & Applications, 2014
At the end of the 1970s, it was confirmed that dielectric multilayers can sustain Bloch surface waves (BSWs). However, BSWs were not widely studied until more recently. Taking advantage of their high-quality factor, sensing applications have focused on BSWs. Thus far, no work has been performed to manipulate and control the natural surface propagations in terms of defined functions with two-dimensional (2D) components, targeting the realization of a 2D system. In this study, we demonstrate that 2D photonic components can be implemented by coating an in-plane shaped ultrathin (l/15) polymer layer on the dielectric multilayer. The presence of the polymer modifies the local effective refractive index, enabling direct manipulation of the BSW. By locally shaping the geometries of the 2D components, the BSW can be deflected, diffracted, focused and coupled with 2D freedom. Enabling BSW manipulation in 2D, the dielectric multilayer can play a new role as a robust platform for 2D optics, which can pave the way for integration in photonic chips. Multiheterodyne near-field measurements are used to study light propagation through micro-and nano-optical components. We demonstrate that a lens-shaped polymer layer can be considered as a 2D component based on the agreement between near-field measurements and theoretical calculations. Both the focal shift and the resolution of a 2D BSW lens are measured for the first time. The proposed platform enables the design of 2D all-optical integrated systems, which have numerous potential applications, including molecular sensing and photonic circuits.
Surface plasmons and Bloch surface waves: Towards optimized ultra-sensitive optical sensors
Applied Physics Letters, 2017
In photonics, the field concentration and enhancement have been major objectives for achieving size reduction and device integration. Plasmonics offers resonant field confinement and enhancement, but ultra-sharp optical resonances in all-dielectric multi-layer thin films are emerging as a powerful contestant. Thus, applications capitalizing upon stronger and sharper optical resonances and larger field enhancements could be faced with a choice for the superior platform. Here, we present a comparison between plasmonic and dielectric multi-layer thin films for their resonance merits. We show that the remarkable characteristics of the resonance behavior of optimized dielectric multi-layers can outweigh those of their metallic counterpart. Published by AIP Publishing.
Bloch Surface Wave-Coupled Emission at Ultraviolet Wavelengths
The Journal of Physical Chemistry C, 2016
The interaction of fluorophores with nearby metallic structures is now an active area of research. Dielectric photonic structures offer some advantages over plasmonic structures, namely small energy losses and less quenching. We describe a dielectric one-dimensional photonic crystal (1DPC), which supports Bloch surface waves (BSWs) from 280 to 440 nm. This BSW structure is a quartz slide coated with alternating layers of SiO 2 and Si 3 N 4. We show that this structure displays BSWs and that the near-UV fluorophore, 2-aminopurine (2-AP), on the top surface of the structure couples with the BSWs. Fluorophores do not have to be inside the structure for coupling and show a narrow angular distribution, with an angular separation of wavelengths. The Bloch wave-coupled emission (BWCE) radiates through the dielectric layer. These BSW structures, with useful wavelength range for detection of intrinsic protein and cofactor fluorescence, provide opportunities for novel optical configurations for bioassays with surface-localized biomolecules and for optical imaging using the coupled emission.