surface plasmon-assisted modification of χ(3) non-linearity in a three-level active medium near gold grating

This study presents a theoretical calculation for the surface plasmon polariton near-field assisted modification of non-linearities of a three-level quantum system placed on top of one-dimensional gold grating structure. the strong coupling of intense electromagnetic near-field, tightly confined at the interface of dielectric-metal grating, can dramatically influence the higher orders of non-linearity of a quantum system placed in the vicinity of grating. we have obtained a full solution of the three-level quantum system problem in our previous study (gupta et al. j opt 18(10):105001, 2016). it can, however, be advantageous to focus on the effects of specific orders of the polarizabilities, particularly at lower intensities of light. it then becomes easier to identify the various effects of the non-linearities on a light probe. in this work, i focus on the χ(3) non-linearity of a given active medium.