26 March 1998 Holographic antireflection coatings
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Using holographic methods to fabricate antireflection coatings is attractive because arbitrarily small reflectivities may be achieved at a single wavelength with a simple photographic process. In this paper, we discuss the theoretical aspects of these holograms and the technical aspects of fabricating them. We present numerical simulations that predict the spectral response of the coating as a function of the bandwidth of the recording source and the thickness and modulation of the emulsion. These results are confirmed with spectrophotometer measurements of actual coatings. Recording holographic antireflection coatings requires a single collimated light source. The hologram-air interface is sued to create the second wave; this allows the coating to automatically correct for variation in the surface of the hologram. However, this method requires a post recording coating procedure to produce a diffracted wave with the correct phase shift. After the hologram is recorded and processed, a thin layer of SiO2 or MgF2 is applied to the hologram to adjust the phase shift between the diffracted wave and the surface reflection. Additionally this coating procedure enhances the durability of the coating and, if MgF2 is used, lowers the refractive index modulation required for complete cancellation of the surface reflection.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jacques E. Ludman, Timothy D. Upton, David W. Watt, and T. Yurovchak "Holographic antireflection coatings", Proc. SPIE 3294, Holographic Materials IV, (26 March 1998); doi: 10.1117/12.304512; https://doi.org/10.1117/12.304512

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