  Subwavelength gratings, with period shorter than the incident wavelength,
have garnered significant attention in the fields of photonics,
optoelectronics, and image sensor technology. In this research, we delve into
the scattering characteristics of these gratings by employing the 2-dimensional
point dipole approximation. Additionally, we propose a version of perturbation
theory that relies on Fourier decomposition to obtain analytical expressions
for the near-field behavior. We validate our models using numerical techniques
such as boundary and finite element analysis. Notably, we explore how
parameters like the grating period and slit width affect field enhancements. We
demonstrate that our models produce qualitatively accurate results even for
narrow slits.
