Understanding a spectral response in a metal–dielectric–metal cavity structure: The role of constituent metals
Incheol Jung, Hyeonwoo Kim, Seung-Hyun Oh, Hojae Kwak, Seongcheol Ju, Misuk Kim, Jong Hoon Jung, Hyoung Won Baac, Jong G. Ok, Kyu‐Tae Lee
Abstract
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.