Polka-Dot BeamsplittersPolka-Dot Beamsplitters

Shimadzu optical device for polychromatic light source splitting and as a substitute for monochromator sector mirrors

Polka-Dot Beamsplitters


  • Wide wavelength range from UV to IR
  • Low dependence on angle of incidence
  • Two types available: standard (to 2200 nm) and high-grade (to 3200 nm) types
  • RoHS*1) compliant
  • *1) RoHS: Directive 2002/95/EC on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment

Polka-Dot Beamsplitters comprise a glass substrate with an aluminum coating in a polka-dot pattern. Incident light is reflected from the coated areas but transmitted through the non-coated areas. This splitting mechanism achieves a light split ratio that is almost independent of the light angle of incidence, unlike dielectric beamsplitters.
Shimadzu Polka-Dot Beamsplitters are based on a synthetic quartz substrate that permits application across a wide wavelength range from the ultraviolet to the infrared.

Product list (table of code numbers)

Click to view a larger image.
Refer to Figures 1 and 2 for detailed characteristics.

Dot pattern chart

Common specifications

Specifications Nominal light ratio
T50/R50 T70/R30 T30/R70
Transmittance*3) 50(+0/-5) % 70(+0/-5) % 30(+0/-5) %
Angle of Incidence 0° to 45°
Wavelength Range Standard : 250 to 2200 nm
High-grade : 250 to 3200 nm
Substrate UV Grade Fused Silica
Coating AL+MgF2
Dimension Tolerance ±0.1 mm
Clear Aperture Full surface, less outer 1.5 mm
Aperture Spacing 0.3 mm
Surface Quality 80-50 (MIL-O-13830A)
Maximum Temperature 150 °C
  • *3) At 555 nm wavelength and 0° angle of incidence

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