First-time detection of calcium carbonate adulteration in food using advanced hexagonal and pentagonal photonic crystal fibers with silica and Schott glass

In this work, we present a novel photonic crystal fiber design for the first-time detection of calcium carbonate concentration using optical fibers. CaCO₃ is a major adulterant in food products such as milk, dairy, flour, spices, confectionery items, and pharmaceutical products. This research analyzes the effect of variable CaCO₃ concentration on various optical parameters like the effective mode index, area, numerical aperture, power fraction, and relative sensitivity of the designed PCF. In our study, we rigorously analyzed four different structures of PCFs using a finite element method. We have numerically analyzed both hexagonal and pentagonal air hole arrangements with two different background materials: Silica and Schott N-BK7 glass. The results indicate that the PCF has higher relative sensitivity and power fraction performance when the air hole lattice is hexagonal, and the background is Silica glass. The results illustrate how PCF geometry and the combination of background materials can make highly sensitive sensors for better food safety applications.