Impact of coupling mirrors on the photonic response of the planar microcavity

In this paper, a silicon-based microcavity consists of a defect layer between different coupling mirrors such as the rugate, Bragg, and sawtooth filters, and a combination of rugate and sawtooth filters is created by electrochemical etching anodization. The spectral response of different silicon-based microcavities is analyzed theoretically by using the transfer matrix method at different incident angles for two different polarization modes (TM and TE). In both TM and TE polarized modes, the resonance line of the sawtooth microcavity is more sensitive to the variation of the incident angles, while the rugate and Bragg microcavities are slightly affected by changing the incident angles. Regardless of the type of mirror, from the angle-dependent reflection dip position analysis, the pass band shifts to a higher wavelength by increasing the incident angle for all the simulated planar microcavities in TM polarized mode, while in TE polarized mode, the resonance position exhibits a blue shift as the incident angles increase. The FWHM of all planar microcavities is affected by changing the angles. We successfully investigated the impact of changing the index contrast and the thickness of mirrors on the spectral response theoretically. The spectral response of the different planar microcavities is investigated through experimentation and simulation. The simulated reflectance spectrum is in good agreement with the experimental one.