Multispectral interference coating with diamond-like carbon (DLC) film

An optical element comprising:

• a substrate having a first surface and a second surface disposed opposite the first surface;
• a first multi-layer dielectric film disposed on the first surface of the substrate and constructed and arranged to transmit light in a first band of wavelengths, the first multi-layer film including a high index of refraction dielectric layer positioned closest to the first surface of the substrate, a medium index of refraction dielectric layer being an outermost layer away from the first surface of the substrate, and a low index of refraction dielectric layer disposed between the medium index of refraction dielectric layer and the high index of refraction dielectric layer;
• a second multi-layer dielectric film disposed on the second surface of the substrate and constructed and arranged to transmit light in a second band of wavelengths, the first and the second bands of wavelengths at least partially overlapping;
• and
• a bilayer diamond-like carbon (DLC) coating disposed on the first multi-layer dielectric film, the bilayer DLC coating including a first layer and a second layer, the first layer having a modulus of elasticity of a first value, and the second layer disposed on the first layer and having a modulus of elasticity of a second value that is greater than the first value.