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Although much thinner than conventional optical interference coatings, nanometer-thick films made of optically absorbing materials can display strong interference effects. This new class of coatings shows promise for coloring and labeling, optical filters, tunable absorbers and emitters, and energy harvesting.

In this work solar cell anti-reflection coatings tuned to give a specific hue under solar illumination are investigated. We demonstrate that it is possible to form patterned coatings with large color contrast and high transmittance. We use colorimetric and thin film optics models to explore the relationship between the color and performance of bilayer anti-reflection coatings on Si, and predict the photocurrent generation from an example Si solar cell. The colorimetric predictions were verified by measuring a series of coatings deposited on Si substrates. Finally, a patterned Si sample was produced using a simple, low-cost photolithography procedure to selectively etch only the top layer of a bilayer coating to demonstrate a high-performance anti-reflection coating with strong color contrast.

Optical interference filters utilizing tunable refractive index layers are shown to have higher spectral fidelity as compared to conventional filters consisting of non-tunable refractive index layers. To demonstrate this increase in spectral fidelity, we design and compare a variety of optical interference filters employing both tunable and non-tunable refractive index layers. Additionally, a five-layer optical interference filter utilizing tunable refractive index layers is designed and fabricated for use with a Xenon lamp to replicate the Air Mass 0 solar irradiance spectrum and is shown to have excellent spectral fidelity.

Measurements are presented of the experimental filters submitted to the first optical thin-film manufacturing problem posed in conjunction with the Topical Meeting on Optical Interference Coatings, in which the object was to produce multilayers with spectral transmittance and reflectance curves that were as close as possible to the target values that were specified in the 400- to 600-nm spectral region. No limit was set on the overall thickness of the solutions or the number of layers used in their construction. The participants were free to use the coating materials of their choice. Six different groups submitted a total of 11 different filters for evaluation. Three different physical vapor deposition processes were used for the manufacture of the coatings: magnetron sputtering, ion-beam sputtering, and plasma-ion-assisted, electron-beam gun evaporation. The solutions ranged in metric thickness from 758 to 4226 nm and consisted of between 8 and 27 layers. For all but two of the samples submitted, the average rms departure of the measured transmittances and reflectances from the target values in the spectral region of interest was between 0.98% and 1.55%.

This paper gives a nonexhaustive review of developments and progress in certain fields of optics, concerning itself mainly with the conception and realization of instruments. Work in instrumental optics is covered, i.e., photographic and astronomical optics, and far uv spectroscopy. Thin film optics, and radio frequency, ir, visible, and near uv spectroscopy are not discussed in view of the fact that they were surveyed in the previous review of optical work in France published in the May 1962 issue of APPLIED OPTICS.

The one-to-one correspondence between transmission line theory and the theory of the optical behavior of thin films is discussed in detail. Advantage is taken of this analogy to apply the methods developed for the solution of transmission line problems to problems involving transparent dielectric films. In particular, the use of Smith charts as a convenient way of doing these calculations is suggested. The reflection from a triple film is worked out to illustrate the general method, and the conditions for zero reflectivity of a single film are deduced in a simple fashion. A variation of the method is then used to derive a new way of obtaining the optical constants of opaque metal films. This method has been applied to aluminum films, and the result obtained is in good agreement with that obtained from polarization measurements.