Bloch waves at the surface of a single-layer coating D-shaped photonic crystal fiber

Abstract

Bloch surface wave (BSW) platforms are particularly interesting for light confinement and surface sensitivity, as an alternative to the metal-based surface plasmon polaritons (SPP). However, most of the reported BSW platforms require depositing a large number of alternating dielectric layers to realize the excitation of the surface waves. In this Letter, we demonstrate an experimentally feasible D-shaped photonic crystal fiber (PCF) platform consisting of only a single dielectric layer on its flat surface, which can sustain Bloch waves at the boundary between the dielectric layer and the PCF cladding. The presence of the dielectric layer modifies the local effective refractive index, enabling a direct manipulation of the BSWs. In addition, the D-shaped structure provides direct contact with the external medium for sensing applications with an ultrahigh sensing figure of merit ( 2451 R I U − 1 ) and has the potential to be used over a wide range of analyte refractive indices.

Novel Bloch wave excitation platform based on few-layer photonic crystal deposited on D-shaped optical fiber

“…5 . As can be seen in these figures, the sensing response exhibits a nonlinear feature, which is due to the wavelength-dependent mode coupling between the core-guided mode and the BSW mode 32 , 43 .…”

“…When the surrounding medium is changed, the evanescent field of the BSW will be affected, and, thereby, the phase matching condition will be altered 43 . In order to characterize the response of the devices presented in the previous section when they are used as refractometers, their 1DPCs were immersed in nine refractive index (glycerol-water) solutions and the generated transmission spectra were captured.…”

“…The resonant generation of BSWs via prims or grating coupling is an active field of current research in applications such as sensors 13 , 21 , 31 , 34 , 35 , surface-enhanced Raman spectroscopy 36 , 37 , fluorescence-based detection 29 , 38 – 40 , enhanced nonlinear effects 41 , 42 , and integrated optics 18 , 20 . However, very few investigations on the BSW excitation in optical fibers have been published, and not all of them have experimental verification 19 , 23 , 30 , 32 , 43 .…”

Design of Phase‐Change Memory Using Apertureless Scanning Near‐Field Optical Microscopy in the Near‐Infrared Region

“…It should be kept in mind that to generate surface plasmon, the real part of the dielectric constant of the metal coating media is required to be negative, and the ratio of its magnitude to that of the dielectric core needs to be limited to certain range. [ 23 ] As a result, the conventional metal medium such as silver and gold, previously adopted for apertureless SNOM in the visible region, cannot be directly implemented here due to their dielectric constant having small negative values (i.e., large absolute values) in the NIR region. It is therefore necessary to seek for another metal coating media that can induce strong surface plasmon effect in the NIR region.…”

Excitation of Hybrid Waveguide-Bloch Surface States with Bi2Se3 Plasmonic Material in the Near-Infrared Range

“…Firstly, BSWs can be excited under both polarizations and any wavelength by changing the composition and parameters of the DBR suitably. In addition, BSWs exhibit much sharper resonances than conventional surface plasmon resonance (SPR) [ 8 , 9 ]. Moreover, the multilayer structure can be fabricated without any pattern, making BSW an attractive optical sensing tool [ 10 , 11 , 12 ].…”