Preparation and characterization of a reference aluminum mirror

Abstract

The preparation and characterization of a reference mirror of protected aluminum (Al) is reported. The mirror is made of 50-60-nm-thick Al film, coated with several-nanometer-thick A12O5 and 30-nm-thick film of AIN. The mirror characterization is based on reliable and precise reflectance measurements relative to a silicon- (Si-) wafer reference mirror. The simple phenomenological Drude-Lorentz model is applied for modeling the dispersion relations n(lambda) and k(lambda) of the Al film. The reflection of the protected Al mirror is determined in the 400-800-nm spectral range with accuracy better than 0.01 for p- and s-polarized light at angles of incidence from 0 degrees to 70 degrees. The accuracy has been confirmed with an evaporated thin silver film with known n(lambda), k(lambda), and d derived by photometric measurements at normal light incidence.

Optically Coated Mirror‐Embedded Microchannel to Measure Hydrophoretic Particle Ordering in Three Dimensions

“…A thin aluminum film is used to enhance the reflectance of a silicon mirror up to more than 80%, which enables imaging of low‐light‐level objects. The typical reflectance of a silicon mirror at wavelengths of 500–800 nm is approximately 35% 13…”

“…To enhance the reflectance from the mirror surface, we fabricated an optical coating on a silicon wafer, known as silvering, in which metals such as aluminum are deposited on glass substrates to make a mirror. The aluminum coating can yield a reflectivity of around 80–90% over the visible spectrum 13. We describe the characterization of an aluminum‐coated silicon substrate for a mirror‐embedded microchannel, and compare it with a bare, uncoated silicon substrate.…”

Thin Chalcogenide Films for Photonic Applications

“…The computer controlled stepper motor of the VASRA accessory ensures reproducible adjustment of the incident angle with an accuracy Δθ = ±0.25º (according to the Cary Operation Manual). A self-made reference Al-mirror, whose preparation and characterization are described in details elsewhere (Babeva et al, 2002), is used as a standard mirror.…”

Optical, electrical, and structural properties of sputtered aluminum alloy thin films with copper, titanium and chromium additions

“…For wavelengths below the IR spectrum, the atomistic or quantum mechanical treatment of dispersion is needed. For aluminum with its high reflectivity and characteristic absorption band near 800 nm, it requires accounting of both inter-and intraband transitions [2,11,12]. There are two known, large interband transitions near the visible range of the spectrum at ∼ 0.5 eV and ∼ 1.6 eV [13].…”

“…The Lorentz-Drude model has been applied to the optical dispersion of aluminum for over 30 years including work by Smith and Segall, Ashcroft and Sturm, Markovic and Rakic, and Bebeva et al [11][12][13]. While this model is not explicitly derived in terms of inter-and intraband transitions, the atomist form has proven useful in experimentation [2].…”