Effect of varying pore size of AAO films on refractive index and birefringence measured by prism coupling technique

Abstract

Anodic aluminum oxide (AAO) films with different pore sizes were prepared to modulate the effective refractive index and birefringence. To investigate the relationship between the refractive index and the pore size of the AAO film, optical constants were obtained using a prism coupler with various lasers. With experimental results, the dispersion curve of alumina itself without pores was extracted using a theoretical anisotropic model. We demonstrated that AAO films could offer a wide range of refractive index and birefringence values for optical device applications. Furthermore, index profiles as a function of the thickness of the AAO films were obtained by inverse Wentzel-Kramer-Brillouin approximation to examine the optical homogeneity.

Shaping the Emission Spectral Profile of Quantum Dots with Periodic Dielectric and Metallic Nanostructures

“…These characteristics suggest that the oscillations in the transmission spectra of the AAO templates originate from the Fabry–Pérot mode interference, which states that the wavelength separation between adjacent transmission peaks can be given aswhere l is the thickness of the cavity, n is the refractive index, and θ is the incidence angle. Taking the transmission spectrum at θ = 0° for the film thickness of 1.7 μm shown in Figure d, the effective refractive index of the AAO template is calculated to be ∼1.52, which is in the typical range of reported values …”

Colour gamuts arising from absorber–dielectric–metal optical resonators

“…The Al substrate is very reflective (∼90%) in the visible range of wavelengths (∼360–780 nm) and the AAO layer is practically lossless ( n = 1.6 ) in this wavelength range. The absorbing layers used are lossy and optically dense, showing high values of the real and complex refractive index ( n and k ) within the visible range.…”

“…In addition, representative points were chosen for each absorber to demonstrate the highest excitation purity for a given hue which can't be attained by the other absorber materials. The Al substrate is very reflective ( $ 90%) in the visible range of wavelengths ( $ 360-780 nm) and the AAO layer is practically lossless (n = 1.6 [36]) in this wavelength range. The absorbing layers used are lossy and optically dense, showing high values of the real and complex refractive index (n and k) within the visible range.…”

Implementation of electrostatically controlled Fabry-Perot interferometer using nanoporous anodic aluminum oxide layer

“…The peculiar optical characteristics of np-AAO film have also been investigated. Furthermore, control of refractive index by adjusting porous structure has been discussed in recent years [3]. Thus, np-AAO is a promising material for electrostatically controlled FPI.…”

“…The merits of this np-AAO Fabry-Perot interferometer are as follows, (1) in-use stiction of the actuation np-AAO membrane can be reduced by the nanoporous textures, (2) dielectric charging can be largely reduced by np-AAO material in this study, thus the offset voltage of the polarities close to zero and hysteresis curves are symmetric [1], (3) driving (pull-in) voltage can be reduced due to superior dielectric constant (ε=7.05) of np-AAO [2], and (4) in addition, refractive index can be adjusted by pore size [3]. The tests demonstrate the performance of presented Fabry-Perot interferometer.…”