• 50/50 Beamsplitting Over a Broad Spectral Range
• Aluminum Coating is Relatively Insensitive to Incident Angle
• Two Substrate Options: B270 Glass or UV Fused Silica

This Ø2" 50/50 Polka Dot Beamsplitter offers a nearly constant beamsplitting ratio over the entire specified spectral range. It consists of a vacuum-deposited aluminum coating on B270 glass, which provides high transmission over the 350 nm - 2.0 µm spectral range. Due to its metal coatings, it can be used through a wide range of incident angles with only negligible changes to the reflected and transmitted intensity.

The aluminum coating is applied in a regularly repeating array, which lends the beamsplitter its "polka dot" appearance. Light is reflected by the aluminum-coated portion of the beamsplitter and transmitted through the uncoated portion of the beamsplitter. To maximize the reflected intensity, light should be incident on the coated side of the beamsplitter. The square dots have 0.0040" (100 µm) long sides, and the spacing between the dots is 0.0022" (56 µm) in all directions.

• Beamsplitting Ratio: 50% ± 5%
• Minimum Beam Diameter for 50/50 Split: 2 mm
• Wavelength Range: 350 nm - 2.0 µm
• Coating Pattern: Square-Coated Apertures
• Clear Aperture: >90% Diameter
• Thickness: 1.5 mm (Nominal)
• Dimensional Tolerance: +0.0 / -0.5 mm
• Angle of Incidence: 0 to 45°