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Polka Dot Beamsplitter, 25.4 mm Diameter, 250-2500 nm
In Stock
In Stock
Polka Dot Beamsplitter, 25.4 x 25.4 mm, 250-2500 nm
In Stock
In Stock
Polka Dot Beamsplitter, 50.8 x 50.8 mm, 250-2500 nm
In Stock
In Stock


  • Wavelength Range
    250-2500 nm
  • Material
    UV Grade Fused Silica
  • Coating Code
  • Angle of Incidence
    0 - 45°
  • Surface Flatness
    1λ wave both sides @ 632.8 nm
  • Surface Quality
    60-40 scratch-dig
  • Thickness
    1.6 mm
  • Thickness Tolerance
    ±0.20 mm
  • Parallelism
    30 arc sec
  • Cleaning


Polka Dot Pattern Beamsplitting

These beamsplitters are coated with aluminum and SiO protective overcoat in a "polka dot" pattern. The pattern is a series of aluminum dots, 2.5 mm in diameter, separated by a 3.2 mm center-to-center distance. Light is reflected by the metal-coated areas of the beamsplitter and transmitted through the uncoated areas of the beamsplitter.

50/50 Split From 250 to 2500 nm

Optimized for white light illumination applications, the smallest beam diameter suitable for a 50/50 split is 0.37 inches (9.5 mm). For beams larger than this, 50% of an incident beam hits the coated area and is reflected. The other 50% of the incident beam hits the uncoated fused silica and is transmitted. Metal is relatively insensitive to the angle of incidence and polarization, so changes to the reflection of the coated area can be neglected over a wide range of incident angles. The reflection of the uncoated area is determined by the Fresnel effect which is angle- and polarization-sensitive, but this is a minor effect except for very high angles of incidence. For angles up to 45°, specified performance can be expected. 

Ideal for White Light Illumination Applications

Our Polka-Dot Beamsplitters are not sensitive to the angle of incidence, so they are well suited to split energy from a radiant light source. These versatile beamsplitters do not exhibit significant divergent effects from diffraction. When they are used with high interference laser beams, it is possible for diffraction to occur. Polarized sources also do not cause any performance issues for these beamsplitters. Polka-Dot Beamsplitters are excellent for use with broadband extended sources, including halogen, tungsten, deuterium and xenon lamps, as well as for use in monochromators, spectrophotometers and a wide variety of optical systems.

Cleaning Polka Dot Beamsplitters

When cleaning Polka Dot Beamsplitters, which have an aluminum coating of halftone dots on a glass substrate, please use care and do not clean these with water or solvents, as this could cause coating deterioration. If possible, use in non-condensing, dust-free environments. If dust or dirt is found, please use compressed air to gently blow the debris off of the surface.