Thorium-free antireflection coatings for domes and windows

Hoa T. Bui; Wasim Hasan

doi:10.1117/12.277045

27 June 1997 Thorium-free antireflection coatings for domes and windows

Hoa T. Bui, Wasim Hasan

Proceedings Volume 3060, Window and Dome Technologies and Materials V; (1997) https://doi.org/10.1117/12.277045
Event: AeroSense '97, 1997, Orlando, FL, United States

Abstract

Thorium fluoride ThF₄ has been used over the last several decades as a low index coating material for many optical applications such as in anti-reflection (AR) coatings, high reflective coating, beam splitters, coating dichroics and optical filters. ThF₄ has excellent optical and mechanical properties but unfortunately is slightly radioactive. New guidelines from many government agencies require that ThF₄ shall not be used as coating material for safety reasons. Also new stringent requirements on the disposal of radioactive material in many states within the USA have made it economically difficult to use. This paper therefore deals with AR coatings which do not have radioactive materials in them. Three types of coatings based on applications have been discussed in this paper. These are namely (1) AR coatings for long wavelength infrared region (LWIR), (2) AR coatings for 1.06 micrometer and long wavelength infrared regions (LWIR), and (3) AR coatings for multiple wavelength regions namely VIS/NIR/MWIR (medium wavelength infrared region) and VIS/NIR/MWIR and LWIR. The spectral performance, mechanical and environmental durability, and rain-erosion test data is presented in this paper.

Citation Download Citation

Hoa T. Bui and Wasim Hasan "Thorium-free antireflection coatings for domes and windows", Proc. SPIE 3060, Window and Dome Technologies and Materials V, (27 June 1997); https://doi.org/10.1117/12.277045

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