Beam-samplers are useful for beam diagnostics and monitoring. They are manufactured to work at 45 degrees incidence. When they transmit the main beam, they sample 4% of the input or so. The sample beam is provided by the natural reflectivity of the surface. The back surface with broadband antireflection coating can eliminate errors from back surface reflections with a high efficiency. 

Our ability can be up to:

Material: BK7A or other materials
Diameter: 2-300mm
Diameter: -0.10mm
Reflectance: R=4% ±1%
Parallelism: <20 arc second
Angle of Incidence:45 degrees
Flatness: λ/10 at 632.8nm
Surface Quality:10-5
Clear Aperture: 90% of Diameter