A broadband antireflection coating for enhanced holographic recording and readout in bismuth silicon oxide
| Autor: | Zaheed Karim, Armand R. Tanguay, Chris Kyriakakis |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) business.industry Holography Dielectric Photorefractive effect engineering.material Diffraction efficiency law.invention Wavelength chemistry.chemical_compound Optics chemistry Coating law engineering Bismuth silicon oxide business Beam (structure) |
| Zdroj: | Applied Physics Letters. 70:2793-2795 |
| ISSN: | 1077-3118 0003-6951 |
| Popis: | We demonstrate a high-quality double-layer antireflection coating for high index (n=2.61 at 514 nm) photorefractive and electro-optic bismuth silicon oxide (Bi12SiO20) crystals. The antireflection coating comprises two electron-beam-deposited quarter-wave dielectric layers of MgF2 and ZrO2, and increases the beam throughput by as much as 20% per interface at normal incidence. For holographic recording applications, the antireflection coating eliminates multiple internal reflections that produce extraneous gratings. The combination of these two factors significantly increases the diffraction efficiency and the two-beam coupling gain. Key characteristics of the double-layer coating include a broadband minimum that encompasses typical write and read wavelengths for Bi12SiO20 with normal-incidence reflectivities of less than 0.2% at 514 nm and 1% at 633 nm, respectively, and a forgiving angular dispersion for both TE and TM polarized waves with reflectivities of less than 2% for angles of incidence up to 45°. |
| Databáze: | OpenAIRE |
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