ML gratings can be overcoated with gold, increasing the reflectivity at 10.6 microns by approximately 1%, but the damage threshold in high power applications may be reduced. No damage threshold minimums apply for overcoated gratings.

Specifications Clear Aperture 90% Groove Parallelism to Edge ± 0.5° Dimensional Tolerances ± 0.5 mm Thickness: Originals 10 mm ± 0.5 mm Replicas 9.5 mm ± 0.5 mm Damage Threshold: Original Gratings: CW Laser 1 KW/cm2 Pulsed Laser (100 nsec pulse) 7 J/cm2 Replicated Gratings: CW Laser 250 W/cm2 Pulsed Laser (200 nsec pulse) 3.5 J/cm2