Reflective Dielectric Coatings as Laser Countermeasures
Technical research rept.
FRANKFORD ARSENAL PHILADELPHIA PA
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Two dielectric reflectors were evaluated. The computer model predictions of the transmission spectra for these reflectors closely reproduced the experimental optical density vs wave-length data for both planes of polarization and for various angles of incidence. The dielectric film designed for use at 1060nm vs neodymium lasers affords good protection against laser radiation up to 70 MWsq cm with luminous transmittance above 90 in the visible region. Optical densities were also measured as a function of angles of incidence of the laser beam on this film. The optical density decreased from about 4.0 to about 3.5 as the angle of incidence increased from normal to about 30 deg. A second reflector was designed to reject both 1060nm and 530nm radiation. This filter exhibited an OD of 2.0 at both 1060 and 530nm. The optical density remained approximately constant for angular deviations to about 40 deg from the normal at power densities up to 65MWsq cm, however, the luminous transmittance was only about 7. Both of these dielectric devices showed good resistance to damage by high power density Q-switched Nd and 2xNd pulses.
- Coatings, Colorants and Finishes
- Optical Countermeasures