Narrow Results

We present a theoretical mechanism for electric field enhancement with SERS of InAs particles of subwavelength apertures under THz excitation. The distribution of electric field confirms that there is a strong enhancement in the InAs particles at THz frequencies. The InAs with a Drude-like behavior in THz range, which is similar to metals at optical frequencies, leads to different SERS when the parameters of these two particles change. The SERS enhancement factor can reach $10^{11}$ under the certain conditions.

Flexible surface enhanced Raman scattering (SERS) substrate was prepared by modification of sandpaper with silver nanoparticles. Under 633 nm excitation wavelength, the SERS enhancement effect of sandpapers which were treated with silver nanoparticles were evaluated by collecting Raman signals of probed molecules. The results demonstrate that the SERS enhancement effect of white (12,000 meshes) is better than that of pink (8000 meshes) sandpaper under the same condition; when the concentration of probe molecules is $10^{-4}$ mol/L, white sandpaper has the best SERS enhancement; the Raman scattering spectrum has better signal when the silver sol is 15 $\mu \mathrm{\text{L}}$.

To explore the strong coupling between the combined plasmonic mode supported by the metal nanoparticle and the anapole mode of the dielectric nanoparticle, a hybrid metal–dielectric nanoparticle consisting of the combination of silicon and silica together with the gold dimer is designed and analyzed by the finite element method (FEM). Theoretical simulation reveals that the enhanced electric field enhancement reaches 640 and unidirectional scattering with almost zero backscattering at multiple wavelengths is achieved in the far-field region. Moreover, the calculated Purcell factor of 12,193 and sensitivity of 610nm/RIU of the composite nanoparticle are much higher than those of the single-metal or dielectric nanoparticles. In the end, the impact of different structural parameters on the sensitivity, figure of merit and quality factor is analyzed and described, and the maximum sensitivity, Figure of merit and quality factor are found to be 2360nm/RIU, 18.4 RIU${}^{-1}$ and 19.8 RIU${}^{-1}$. The results reveal a new strategy to develop devices for surface-enhancement Raman scattering (SERS), quantum emitters, and sensors.