During this past year, National Technical Systems (NTS) optics group has been successful in fabricating super high efficiency holographic reflection coatings with optical density of 6 and with reflectivity 99.9% for the visible portion of the spectrum. Most recently, NTS was able to extend these holographic coatings into the IR region of the spectrum. The holographic coatings are 10 micrometers thick and have extremely small absorption. Electron micrographs have shown the index of refraction to be of a sinusoidal form (i.e., a natural rugate filter). These holographic coatings have properties that exceed the best dielectric stacks at a projected cost of fabrication that is two orders of magnitude less than dielectric mirrors. Thus, the possibility of using these holographic coatings as a passive means for target hardening against various visible and IR laser weapons suggests itself. The ability to deflect/reflect small wavelength regions (delta lambda approx 20 nm) has been demonstrated against low power laser threats over small areas since these holographic coatings are fabricated with a laser beam, the only limitation to fabricating large area (approx m2), is the ability to diverge (spread out) the laser beam so that it is still uniform over the surface of the hologram.
