Light localization and SERS in tip-shaped silicon metasurface

Abstract

Optical properties of two dimensional periodic system of the silicon micro-cones are investigated. The metasurface, composed of the silicon tips, shows enhancement of the local optical field. Finite element computer simulations as well as real experiment reveal anomalous optical response of the dielectric metasurface due to excitation of the dielectric resonances. Various electromagnetic resonances are considered in the dielectric cone. The metal-dielectric resonances, which are excited between metal nanoparticles and dielectric cones, are also considered. The resonance local electric field can be much larger than the field in the usual surface plasmon resonances. To investigate local electric field the signal molecules are deposited on the metal nanoparticles. We demonstrate enhancement of the electromagnetic field and Raman signal from the complex of DTNB acid molecules and gold nanoparticles, which are distributed over the metasurface. The metasurfaces composed from the dielectric resonators can have quasi-continuous spectrum and serve as an efficient SERS substrates.

Fabrication and SERS Performances of Metal/Si and Metal/ZnO Nanosensors: A Review

“…Furthermore, this group also showed that the thickness of the metallic layer (for gold) has an effect on the SERS enhancement [59]. Lastly, other groups also demonstrated SERS enhancements with other shapes of Si nanosystems such as a tip-shaped silicon metasurface coated with gold nanoparticles [67,68], a hybrid Si nanospheroid network ornamented with gold nanospheres [69], silver-coated Si nanopores [70], or Si nanowire arrays coated silver nanoparticles [71,72]. To conclude Section 2, the interests of the metal-coated Si nanosystems are the use of fabrication techniques known as large-surface techniques, and also the plasmonic coupling between the metallic layer/nanoparticles and the semiconducting silicon substrate [38,58,73] in order to potentially improve the Raman enhancement.…”

Light Concentration by Metal-Dielectric Micro-Resonators for SERS Sensing

“…EM resonances in a dielectric lamp, whose symmetry is less than spherical symmetry, may have quasi-continuous spectrum (see Ref. [18]). Small clusters of metal particles are considered in [191].…”

“…In Ref. [18], Lagarkov et al have studied the light interaction with a tip-shaped metasurfaces composed of silicon cones (see Figure 25).…”

“…A HeNe laser false(λ = 632.8 nm) illuminates the sample (metasurface) and reflects from this sample by producing a diffraction pattern on the other side of the screen as displayed in Figure 26. The parameters and settings are available in [18]. The diffraction pattern contains all the 37 modes having different radiances Ifalse(m1,m2false) as shown in Figure 26.…”

“…A strongly amplified electromagnetic field can be generated by disordered metal-dielectric composites in a broad spectral range [9]. Periodically ordered nanostructures enhance local EM field at selected frequencies [10,11,12,13,14,15,16,17,18,19,20,21,22,23]. Plasmon modes propagating in a chain of metallic nanoparticles, where the particle radius a is relatively equal to the distance δ between particles, are precisely investigated in [24].…”