Abstract

This paper presents data on the optical properties of evaporated MgO films in the wavelength region from 0.22 μ to 8 μ. The films were deposited in high vacuum with an electron gun at a rate of about 20 Å/sec, and their refractive indices were determined using three different techniques. The absorptance of the films was found to be negligible over the wavelength region measured. Films deposited on substrates of 50°C had refractive indices of 1.70 at λ = 0.55 μ and 1.62 at λ = 4 μ, while those condensed at 300°C showed at the same wavelengths n-values of 1.74 and 1.66, respectively. All MgO films were found to be crystalline showing the cubic structure and lattice constant of the bulk material. Their crystal size increased with increasing substrate temperature. MgO proved to be a suitable film compound for producing three-layer antireflection coatings on glass. It can also be used in combination with SiO₂ or MgF₂ for preparing protected Al front surface mirrors with 95% reflectance at λ = 0.25 μ. During extended exposure to normal air a hazy, bluish scattering coating forms on the surface of MgO films that limits their usefulness as an optical coating material.

© 1972 Optical Society of America

Reflectance of Evaporated Rhenium and Tungsten Films in the Vacuum Ultraviolet from 300 to 2000 Å*

J. T. Cox, G. Hass, J. B. Ramsey, and W. R. Hunter
J. Opt. Soc. Am. 62(6) 781-785 (1972)

Optical Properties and Structure of Cerium Dioxide Films

G. Hass, J. B. Ramsey, and R. Thun
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Vacuum Deposition of Dielectric and Semiconductor Films by a CO₂ Laser

G. Hass and J. B. Ramsey
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Monitoring the Thickness of Thin MgF₂ and LiF Films on Al by Reflectance Measurements Using the 1216-Å Line of Hydrogen

E. T. Hutcheson, J. T. Cox, G. Hass, and W. R. Hunter
Appl. Opt. 11(7) 1590-1593 (1972)

Effect of Deposition Rate and Substrate Temperature on the Vacuum Ultraviolet Reflectance of MgF₂- and LiF-Overcoated Aluminum Mirrors

E. T. Hutcheson, G. Hass, and J. T. Cox
Appl. Opt. 11(10) 2245-2248 (1972)