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Home / Product / Thin Film Coatings / DST Beamsplitters



Special Characteristics

  • Low-loss dielectric optical layer design
  • Made for random polarized light
  • Rear side with antireflection coating
  • Largely color neutral
  • Strong suppression of ghost images
  • High optical quality
  • Non-metallic thin film cotings
  • Designed for 45° incident angle use
  • Large dimensions available (DST500)

Typical Applications

  • Efficient division of light beams and images
  • Optical reference measurement systems
  • Fiber optical beamsplitter
  • Optics for interferometer systems
  • Laser beamsplitter up to medium beam powers
  • Sensor technology
  • Teleprompter mirrors
  • Beam combiners for lasers
  • Half-mirrors
  • Photonics applications
  • Semi-transparent mirror optics

How our plate beamsplitters work

Beamsplitters are found in optical reference measurenent systems, opto-electronics, fiber optics, photonics and in laser applications and they are mainly used to split an incident light beam into two separate light beams. To achieve this, the input side Plate beamsplitters used as laser beam dividerof each beamsplitter is vacuum coated with a dielectric, partially transparent optical thin film coating. The back side is coated with a broadband anti–reflection coating in order minimize undesired secondary reflections from the substrate. This effectively prevents ghost images or interfering double beam reflections of lasers as well as optical reflection losses, which otherwise would be produced from an uncoated back side of a beam-splitter. All of our plate beamsplitters are designed for a defined splitting ratio (R : T) for visible, random polarized light at an incidence angle of 45°.

Design and special properties

Unlike dichroic beamsplitters, our DST is conceptualized to be largely color neutral over the full operating wavelength spectrum. Due to the metal-free construction, our coatings offer a high scratch resistance and better durability than most metal-based beamsplitters. Moreover, the vacuum deposited, non-metallic, 100 % dielectric optical coating system, offers a very low absorption in the visible range, which keeps the loss of light energy negligible. Flat laser beam dividing optics The average optical energy absorption in the nominal wavelength range typically is less than 1 %. In terms of efficiency, this is a considerable improvement over metal based beamsplitters, which often absorb a large portion of the incident energy. Hence, the efficient dielectric layer design makes our beamsplitters an ideal choice to be used to split laser beams up to medium laser powers. The power the beamsplitters can withstand, depends on the laser beam diameter and on power of the laser and therefore on the power density of the laser beam used. Because our DST-series are designed to split light with random polarization, the splitter ratio for light and laser beams with polarization can deviate from the ratios shown in this data-sheet, which are all specified for unpolarized light. Therefore we do not make statements about polarization effects that may arise when our DST is used with polarized lasers or with other polarizing light sources.

In cases you need a specific beamsplitter model for polarized light or if you need polarization optimized beamsplitter optics for lasers, we can create a customized solution, based on your exacting polarization requirements. Please consider, that custom designed optics must be manufactured in production batches. The production of single pieces of complex, customized coatings is extremely uneconomical.

Standards and custom beamsplitters

In addition to our standard DST-series, which is available from stock, the dividing ratios of our beamsplitter optics can be customized in, based on a coating-run. At adequate quantities we can also manufacture optical cube -, high power laser beam-, polarizing-, dichroic cube-, near infrared, fiber-optical beamsplitters as well as beam-splitter-prisms. Because these kind of optics are custom-made, they are only manufactured on demand. Please use our custom optics inquiry-form to get a quotation for a batch of a high precision cube beamsplitter or for a beamsplitter prism. If you need engineering support or guide for the optical design, please do not hesitate to contact our staff.

How can I purchase the DST beamsplitters?

We are not confined to a few stock sizes. This is why you will not find a shopping cart on our website. We are well organized and specialized in terms of quick manufacturing of our optical DST beamsplitters at customized dimensions. In most cases, we can supply customized sizes as fast or even faster than ususally stock items are supplied. This often even is possible at large production quantities. To get a quotation for one of our DST beamsplitters, please click on the button below, which will guide you to our inquiry form:


Request for Quotation

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48-h Express Optics Service available



DST300, transmittanceDST300, spectral transmittance curve for visible wavelengths

DST300 at wavelength 400-700 nm


DST500, transmittanceDST500, typical transmittance for visible wavelengths

DST500 at wavelength 400-700 nm


DST700, transmitanceDST700, typical spectral transmittance for visible light

DST700 at wavelength 400-700 nm


Product Codes

(Reflection (R) : transmission (T),
defined for unpolarized light beam)
  • DST300 (R : T = 70 : 30)
  • DST500 (R : T = 50 : 50)
  • DST700 (R : T = 30 : 70)
  • Other dividing ratios and angles possible on demand

Substrate Materials

Optical Coating Definitions

(All for an incidence angle of i=45°, random polarization)

  • R : T = 70 : 30 (± 10 %) at wavelengths
    of 450-650 nm
    (Typical ratios for the use with lasers per inquiry)
  • Rear side with broadband BBAR
  • Stock thickness 1,00 mm (+/-0,1)
  • R : T = 50 : 50 (± 6 %) at wavelengths
    of 450-650 nm
  • R : T = 50 : 50 (± 10 %) at 430-685 nm
    (Typical ratios for the use with lasers per inquiry)
  • Rear side with broadbwand AR
  • Standard thickness 1,00 mm (+/-0,1)
  • R : T = 50 : 50 (± 10 %) at wavelengths
    of 450-650 nm
  • R : T = 50 : 50 (± 10 %) at 430-700 nm
    (Typical ratios for the use with lasers per inquiry)
  • Rear side with broadband AR
  • Stock thickness 3,30 mm (+/-0,2)
  • R : T = 30 : 70 (± 8 %) at wavelengths
    of 450-650 nm
  • R : T = 30 : 70 (± 10 %) at 400-700 nm
    (Typical ratios for laser beam use per inquiry)
  • Rear side BBAR-coated
  • Stock tk. 1,00 mm (+/-0,1)


  • Depending on material, thickness and shape
    (flat, cube, prism etc.)

Damage Threshold (laser use)

  • Depending on laser beam diameter and laser power (Please send an inquiry for information)

Surface Quality

  • Typically better than 80-50 scratch & dig
  • Other per inquiry


  • up to approximately 630 mm x 810 mm
    (flat optics only. Cube-, polarizing-, non-polarizing or prism beam splitters etc. are not feasible at such large dimensions. Please discuss the limits with our engineers.)

Other Specifications

  • Adherence according to MIL-C-675 C (tape test)
  • Abrasion resistance referred to MIL-M-13508 C


All given details and specifications are mean reference values and are not guaranteed. In addition, please consider our "Notes on technical specifications"