Fig. 1: Experimental setup and FEM model-based nano scale thickness estimation for EFBG.

a Schematic illustration of the experimental setup of LbL deposition on EFBG. Inset (a) Schematic diagram of FEM model for EFBG for generating thickness data from experiments. b Thickness values \((t)\) in nm for different values of Bragg wavelength shifts \((\Delta {\lambda }_{B})\) using exponential growth model of the FEM model.