Tunable Bloch surface wave constructed by two-dimensional lithium niobate grating for biosensor

Abstract

In this study, a Bloch surface wave (BSW) biosensor coupled with a two-dimensional lithium niobate grating was designed. The influence of the nonlinear characteristics of lithium niobate on the BSW sensor was theoretically investigated, and the tunability of the BSW was studied using the excitation schemes of ne and no. To confine the energy on the surface of the solution in contact with the sensor, we introduce a distributed Bragg reflector mirror (DBR) consisting of four pairs of 76% and 42% porosity porous silicon films. A layer of lithium niobate grating is deposited on top of DBR to excite Bloch surface waves (BSW)and introduce the concept of azimuth detection in the study of the tunable properties of lithium niobate. Then, the azimuth angle of the resonance peaks excited along the ne and no directions of lithium niobate varied by approximately 5°.

Design and optimization of Bloch surface wave sensor with high sensitivity and quality factor using LiNbO3

“…10,11 Therefore, improving sensing performance has been pursued by replacing the metallic layer with one-dimensional photonic crystal dielectric materials to excite BSWs, which exhibit similar characteristics to SPR. 12 BSW can be excited through various methods, including prism coupling, 13 nanoparticles, 14,15 and gratings, 16,17 and it can be excited at different polarization states (P-polarized and S-polarized) and wavelengths. Since BSW does not rely on precious metal materials, its reflection spectrum exhibits sharper peaks, 18 resulting in higher sensor quality factors and lower costs.…”