Bloch Surface Wave Resonance Based Sensors as an Alternative to Surface Plasmon Resonance Sensors

Abstract

We report on a highly sensitive measurement of the relative humidity (RH) of moist air using both the surface plasmon resonance (SPR) and Bloch surface wave resonance (BSWR). Both resonances are resolved in the Kretschmann configuration when the wavelength interrogation method is utilized. The SPR is revealed for a multilayer plasmonic structure of SF10/Cr/Au, while the BSWR is resolved for a multilayer dielectric structure (MDS) comprising four bilayers of TiO2/SiO2 with a rough termination layer of TiO2. The SPR effect is manifested by a dip in the reflectance of a p-polarized wave, and a shift of the dip with the change in the RH, or equivalently with the change in the refractive index of moist air is revealed, giving a sensitivity in a range of 0.042–0.072 nm/%RH. The BSWR effect is manifested by a dip in the reflectance of the spectral interference of s- and p-polarized waves, which represents an effective approach in resolving the resonance with maximum depth. For the MDS under study, the BSWRs were resolved within two band gaps, and for moist air we obtained sensitivities of 0.021–0.038 nm/%RH and 0.046–0.065 nm/%RH, respectively. We also revealed that the SPR based RH measurement is with the figure of merit (FOM) up to 4.7 × 10−4 %RH−1, while BSWR based measurements have FOMs as high as 3.0 × 10−3 %RH−1 and 1.1 × 10−3 %RH−1, respectively. The obtained spectral interferometry based results demonstrate that the BSWR based sensor employing the available MDS has a similar sensitivity as the SPR based sensor, but outperforms it in the FOM. BSW based sensors employing dielectrics thus represent an effective alternative with a number of advantages, including better mechanical and chemical stability than metal films used in SPR sensing.

Efficient Optical Sensing Based on Phase Shift of Waves Supported by a One-Dimensional Photonic Crystal

“…In resulting eigenproblem, eigenvalues of the transmission matrix are related to the Bloch wave number K . For derivation, see [ 45 ] and resulting equation for p -polarized light is [ 16 ] where a , b and are thicknesses of the layers and a bilayer thickness, respectively, , is a normal component of a wave vector in corresponding medium and is a propagation constant. Equation ( 15 ) gives dependence of the propagation constant on the angular frequency .…”

“…The 1DPhCs can also act as planar waveguides [ 4 ] and the guided waves (GWs) can be used in sensing applications [ 5 , 6 , 7 ]. Last but not the least, the Bloch surface waves (BSWs) propagating along the interface of the 1DPhC with an external medium are widely used in sensing, including the angular [ 8 , 9 , 10 , 11 ] or wavelength [ 12 , 13 , 14 , 15 , 16 , 17 ] interrogations. Thus, the BSW-based sensors extend mature technologies applied in sensing that have several applications in different fields of biology [ 18 ], physics [ 18 ], and chemistry [ 18 , 19 , 20 , 21 ].…”

“…Therefore, sensors based on the phase detection of waves supported by a 1DPhC are feasible [ 22 , 23 , 24 , 25 , 26 , 27 ]. In addition, they represent an alternative to relative humidity sensors based on resonances of surface plasmons [ 16 ], BSWs [ 16 ], whispering gallery modes [ 28 ], guided modes [ 4 , 7 , 29 ], photonic crystal modes [ 30 ], and lossy modes [ 31 , 32 ].…”

Subtle Application of Electrical Field-Induced Lossy Mode Resonance to Enhance Performance of Optical Planar Waveguide Biosensor

“…However, the sensitivity of SPR sensors cannot be increased [ 5 ]. A finite one-dimensional photonic crystal (1DPC) structure for an electromagnetic waves propagating at the interface between a homogeneous medium, which are named Bloch surface waves (BSWs), have found a large number of applications [ 6 , 7 , 8 ] and were proposed as an alternative to SPR [ 9 ]. Contrary to SPPs, the BSWs can be excited by both s- and p-polarized waves by changing the geometry and materials of the photonic crystal.…”

“…Their dispersion can be designed at almost any wavelength by properly choosing the refractive index and thickness of the layers of the 1DPC. Owing to the dielectric materials of the photonic crystal, sensors based on BSWs are characterized by mechanical and chemical stability, thus permitting operation in aggressive environments [ 9 ]. However, 1DPC is a multi-layer stacked structure where a complex and precise coating process is required and that will increase the difficulty of sensor production.…”