No abstract

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%.

No abstract

Acting as a prime contractor to the Gemini PrOJeCt [GPJ, the Optical Data Associates [ODA] . with Its major subcontractors, BOC Coating Technologies IBOCC11 and Deposition Sciences, Inc. IDSII, developed options for depositing protected silver coatings on the 8-M primary mirroi. The project began with a study that identified sputtering as the preferred deposition technique, defined a set of candidate adhesor and protective coatings for the silver layer, and simulated stack performance. The next phase involved pilot magnetron sputtering studies by BOCC and DSI of designs lnvoMng silicon nitride and hafnla, respectively. ODA also developed mid-IR reflectance standards at . = 10.6 pm to control the silver coating measurements In the critical 8-12 pin atmospheric window. The study. results were successful, with both BOCCI and DSI producing Ag coatings with R = 0.9920 0.0001 and protected Ag coatings with R = 0.9910 0.0001 . The Gemini Project coating plants are designed to sputter bare and protected Al and Ag coatings.

Results are presented for the second Optical Society of America's Optical Interference Coatings Manufacturing Problem. The participants were asked to produce multilayer coatings which, in the 450-650 nm spectral region and for light incident at 60 degrees, would have transmittances of 0.7 and 0.3 for p- and s-polarized light, respectively. Three different teams each submitted four solutions. Three different deposition processes were used to produce these coatings. The smallest average departure from the target transmission values was 0.79%. A number of interesting conclusions can be drawn from this exercise.