The simplest of all AR coatings, this consists of a single layer of MgF2 on the substrate. It is cost friendly because it can be done on simple, inexpensive machines. It is more effective on high index glasses. We take an example of a three element camera lens. The lenses are all of high index glasses and exhibit reflections of up to 8% per surface. This means that only 92% of the light would pass through from each surface. At the end of three lenses (and 6 surfaces), less than 70% of the light would pass through the system. This would result in tremendous loss of light, reducing picture clarity and inducing ghost reflections. If all the surfaces are coated with SLARC, an average of 95% of light passes through the assembly resulting in much sharper images and no
ghost reflections. The picture shows reflection of uncoated surface of N-BK7 as well as one having SLARC coating, at normal incidence. This coating gives an average reflection of 1.5% per surface and is useful from angles of incidence from 0° to 30°.The coating can be tuned for other wavelengths from UV to IR region.
SLARC cannot be used in all applications. There are applications which need lower reflection over a broad range of wavelengths. These require multi-layers which are more complicated. These can be for UV region, for visible region, IR region. These can be designed and tuned for the required wavelength range and for all kinds of substrate materials.
These are coatings designed for specific wavelengths. They can be tuned for any required wavelength from UV to IR region. These can give reflection as low as 0.1% per surface. We also do 1064nm coatings with high damage threshold.
These coatings are designed for 2 different wavelengths or wavelength ranges.