We report on the optical properties of the CuCl microcavities that exhibit fluctuations in their refractive index profiles along the cavity structures. The angle-resolved reflectance spectra of the CuCl microcavities with a cavity length of half-integer multiples for the $Z_3$ exciton wavelength clearly show three cavity-polariton modes and minor modes. The Rabi splitting energies observed in the cavity-polariton modes are widely controlled by changing the cavity length of the microcavity. To analyze the spectral profile and the Rabi splitting energies qualitatively, the refractive index profiles of the constituent layers in the CuCl microcavities are evaluated using spectroscopic ellipsometry, and the reflectance spectra of the CuCl microcavities with the fluctuations in the refractive index profiles of the microcavity structures are calculated using the nonlocal response theory. The calculated reflectance spectra reproduce very well the cavity-polariton modes and the minor modes, including their energies and spectral profiles, in the observed reflectance spectra, which indicates an essential role of the fluctuation effect of the refractive indices of constituent layers in controlling the Rabi splitting energies and the quality factor of the microcavity.

• Received 5 June 2013

DOI:https://doi.org/10.1103/PhysRevB.88.205311