Tip-Enhanced Raman Scattering in Epsilon-Near-Zero Nanocavity

Observation of molecular optomechanical effects is complicated by the need to localize electromagnetic energy in metal gaps about 1 nm in size. We propose to use a nanocavity with an epsilon-near-zero medium so that the conditions required for optomechanical coupling are less stringent. In this work, we simulate the enhancement of Raman scattering depending on the permittivity of the material and the polarization of the near field of the nanoparticle. It is shown that when the real part of dielectric permittivity close to zero, Raman scattering demonstrates an additional enhancement.