TY - CONF

T1 - Shift-free fixed-line laser protection filter technology

AU - Wang, James

PY - 2020/10/7

Y1 - 2020/10/7

N2 - The development of shift-free fixed-line filters is a key technology for advancing the next generation of laser protection and is greatly desired due to the increased threat of laser attacks. Thin-film interference coatings have remained the key technology for achieving narrow bandstop filters for protection against laser light since the late 1970s. This paper presents the latest developments in fixed-line laser technology and introduces a metamaterial solution to mitigate the angular shift found in thin-film interference coatings. The metamaterial coating consists of metallic nano-particles periodically distributed within a non-absorbing dielectric material with a specific refractive index that enables the desired plasmonic resonance to exist at wavelengths that match that of the lasers. Due to the nano-particle size, the metamaterial layer can be treated as an individual homogeneous layer with properties described by an effective Drude-Lorentz approximation model. Unlike standard interference coatings where the effective index of the stack decreases with larger angles of incidence, the metamaterial’s effective index remains relatively fixed with increasing angles resulting in the narrow bandstop function remaining shift-free.

AB - The development of shift-free fixed-line filters is a key technology for advancing the next generation of laser protection and is greatly desired due to the increased threat of laser attacks. Thin-film interference coatings have remained the key technology for achieving narrow bandstop filters for protection against laser light since the late 1970s. This paper presents the latest developments in fixed-line laser technology and introduces a metamaterial solution to mitigate the angular shift found in thin-film interference coatings. The metamaterial coating consists of metallic nano-particles periodically distributed within a non-absorbing dielectric material with a specific refractive index that enables the desired plasmonic resonance to exist at wavelengths that match that of the lasers. Due to the nano-particle size, the metamaterial layer can be treated as an individual homogeneous layer with properties described by an effective Drude-Lorentz approximation model. Unlike standard interference coatings where the effective index of the stack decreases with larger angles of incidence, the metamaterial’s effective index remains relatively fixed with increasing angles resulting in the narrow bandstop function remaining shift-free.

U2 - 10.1117/12.2573993

DO - 10.1117/12.2573993

M3 - Paper

T2 - Technologies for Optical Countermeasures XVII; and High-Power Lasers: Technology and Systems, Platforms, Effects IV

Y2 - 20 September 2020

ER -