Role of cavity length in tuning the position of resonance peaks in Fabry Perot interferometer

Tuning of resonance peaks varying the cavity lengths in the Fabry Perot interferometer is of great interest in optoelectronic device applications such as optical filters. To achieve this, we first make use of Maxwell’s equation to theoretically investigate the relation of transmission and reflectance of a multilayer system and determine the transmission and reflection spectra of the distributed Bragg reflectors (DBR) in the system. Taking one of the most common lowest refractive index coating materials MgF₂, and relatively high refractive index material TiO₂, in layers of the system, the transmission and reflection spectra of the Fabry Perot interferometer constructed from them are evaluated. The same is evaluated by replacing one of the layers with MXene and graphene. The optical spectra are observed as a function of cavity length to analyze the resonant peak position variation with respect to the cavity length. We noticed that the DBR system blocks the wide range of the frequency band. The cavity formed between the two DBRs causes the formation of a transmission peak within the stop band whose position changes with the cavity length change. This work is supported by the Department of Energy BES-RENEW award number DE-SC0024611.