A simple matlab program to visulize "local field factor" in a thin film reflection experiment, such as boron nitrid(BN) sandwiched transition metal dichalcogenide(TMD) layers on Si/SiO2 substrate. Depending on the BN thickness, the reflection of spectrum of the sample can be different, as shown below:

Future features: Extracting out dielectric function given spectrum and configureation; Simple UI to customize layers