Exceptional Transparency Window in a Finite Alternating Stack of Ag and CuCl Films

Abstract

I show that the transmission coefficient of light propagating normally to the face of a stack of thin alternating films of silver and CuCl may exhibit a narrow exceptional transparency window at a frequency slightly lower than the excitonic resonance frequency. This window is caused by the coupling of the plasmon mode of the metal with the excitonic mode of the semiconductor and is principally due in the present system to the strong oscillator strength and the narrow width of the CuCl excitonic mode.