Glenn A. Clarke

High-rate automated deposition system for the manufacture of complex multilayer coatings.

A previously described automated thin-film deposition system based on rf-magnetron sputtering could deposit quite complex optical multilayer systems with good precision and with no one in attendance [Sullivan and Dobrowolski, Appl. Opt. 32, 2351-2360 (1993)]. However, the deposition rate was slow, and the uniform area on the substrate was limited. We describe an ac-magnetron sputtering process in which the same deposition accuracy has been combined with significantly better film uniformity and a fivefold or sevenfold increase in the deposition rate. This makes the equipment of commercial interest. Experimental results are presented for several difficult coating problems.

Design and manufacture of all-dielectric nonpolarizing beam splitters

Past research on all-dielectric nonpolarizing beam splitters is reviewed. It is shown that, for a 50-nm spectral region, it is possible to design and manufacture a two-material nonpolarizing plate beam splitter for use at an angle of 45 degrees (with a measured rms reflectance of 0.50 +/- 0.01 for both s- and p-polarized incident light).

Manufacture of complex optical multilayer filters using an automated deposition system

Abstract It is now possible to design complex thin film multilayer coatings that can achieve almost any desired spectral performance. Moreover, these coatings can consist of tens or hundreds of layers each of which may have a different thickness. It is a challenge to accurately manufacture such complex coatings. An automated deposition system (ADS) has been developed which is able to fabricate complex optical coatings on a routine basis. This deposition system uses a wideband optical monitor to accurately determine the deposited layer thickness and to re-optimize the remaining layer thicknesses, if required. One advantage of this process is that no operators are required during the manufacture of a filter. For this technique to work, however, an energetic deposition process such as sputtering is necessary in order to achieve thin films with a bulk-like refractive index with little or no porosity or inhomogeneity. As well, the optical constants of the thin film materials must be accurately known. A number of thin film filters have been manufactured using this ADS. These include all-dielectric coatings as well as metal/dielectric filters. In this paper, the ADS and the real-time process control algorithms will be described in more detail and several examples of manufactured complex thin film filters will be described for different applications.