Understanding a spectral response in a metal-dielectric-metal cavity structure: The role of constituent metals

Understanding optical interference in multilayer structures is of critical importance for designing a variety of optical coatings that have been widely used as an essential element in diverse applications. We demonstrate that the transition of reflective properties from a valley to a peak occurs by a metal on the incident side in a cavity structure comprising a transparent dielectric medium surrounded by two metals. The reflected light destructively interferes giving rise to a reflection dip when there is a large difference between the refractive index and the extinction coefficient of the metal, whereas a constructive interference occurs with the refractive index that is comparable to the extinction coefficient yielding a reflection peak. In addition, an admittance and an electric field distribution of the cavity structure are investigated with different constituent metals. Our results described in this paper provides a better understanding of the fundamental principles of the optical cavity, thereby potentially extending the range of possible future applications.

Automated summary

Understanding optical interference in multilayer structures is crucial for designing optical coatings used in various applications. By studying a cavity structure with a transparent dielectric medium surrounded by two metals, we show that the reflective properties transition from a valley to a peak when a metal is present on the incident side. This transition occurs due to destructive and constructive interference of the reflected light, depending on the refractive index and extinction coefficient of the metal. Furthermore, we investigate the admittance and electric field distribution of the cavity structure with different constituent metals. Our findings provide valuable insights into the fundamental principles of optical cavities and have the potential to expand future applications.