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45°-Beam splitter plates, DST Series

Special Properties & Features

  • Color neutral splitting of light and images
  • Anti-reflection coated backside
  • Free of double images or phantom laser beams
  • Low-loss dielectric coating
  • Non-metallic thin film construction
  • Designed for random polarization
  • High optical quality
  • Available with large dimensions (DST500) NEW!

Typical Applications

  • Optical reference measurement systems
  • Laser beamsplitters
  • Semi-transparent mirrors for interferometer systems
  • Splitting or merging of beam paths
  • Sensor technology
  • Fiber optical applications
  • Image processing
  • Machine vision
  • Photonics research
  • Beamsplitter plates in optical instruments
  • Laser beam combiners
  • Measurement technology
  • Divider mirrors for imaging applications


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48h-Express Service Also available in 48 h Express-Service


Plate beamsplitters used as laser-beam dividerOur DST beamsplitters divide an incident light beam into a transmission and a reflection component. The incident light or an image is partially reflected as through an optical mirror and partially transmitted as through an optical window. The input surface of our beam splitter plates is coated with a very thin dielectric coating, which determines the splitting ratio. On the rear side, the DST beamsplitters have a broadband anti-reflection coating which almost wholly eliminates secondary reflections, so-called ghost images or phantom laser beams. Losses due to reflections on the rear glass surface can thus almost not occur.

Unlike dichroic beamsplitters, such as our SIR filters or SHD mirrors, DST optical splitter mirrors do not work like dichroic optics. They do not separate different light spectra from each other but divide the incident light rays in the visible range in a largely color-neutral way. A non-metallic construction of our beamsplitters ensures excellent durability and abrasion resistance. Besides, the dielectric layer system of the splitter mirrors has very low absorption in the nominal wavelength range. In contrast to metallic beamsplitter plates, very little light is absorbed. Hence, DST-beam splitter plates can also be used as beam splitters for lasers. In this application, a part of the laser beam is mirrored by 45°, while the rest of the beam is transmitted at 0° (see picture below). This function is often required in optical benches and reference measurement systems.

Flat laser-beamsplitter opticsAll DST beamsplitters are designed for light without defined polarization, i.e. unpolarized light. When using DST splitter mirrors with polarized light sources or with a polarized laser, the optical splitting ratios may therefore deviate from the specifications given here, as these are given in this data sheet exclusively for randomly polarized light. The DST beamsplitters are undefined in terms of polarization or polarization effects. However, this does not generally exclude an application with polarized light sources. Often the desired gradation can be achieved by selecting a higher or lower, already existing ratio and the costs can be drastically reduced compared to a customer-specific coating batch. If you need a beam splitter plate for polarized light or a polarized laser, please contact us with information on wavelength, splitting ratio and all relevant details for your application. In case of special requirements regarding polarization properties, we can usually also manufacture polarization-optimized, customer-specific divider optics with sufficient production quantities.

In addition to our standard beamsplitters, the DST300, DST500, and DST700 series, we can also coat splitting ratios according to customer specifications. Also feasible on a batch basis are polarizing beam splitter cubes, beamsplitter pentaprisms, NIR splitter mirrors, and high-performance beamsplitters. Design and production of polarizing beam splitter cubes, as well as polarization direction maintaining splitter optics, can also be realized. Such beamsplitter components are always customized and are therefore not listed in detail on our website. Please use our inquiry form to request customized beamsplitter optics, technical assistance, and further information.


How can I order the standard beamsplitters?

You will not find any shopping cart on our website, because we are not limited to standard items with fixed dimensions. We are specialized in manufacturing and delivering our DST dividers with customized sizes very quickly. Therefore, we often ship tailor-made beamsplitters just as fast or even faster than standard stock items. Moreover, this also applies to large production quantities! As a rule, you will receive our quotation within a few minutes, provided you are in our time zone and there are no queries.

To request a quote for one of our DST beamsplitters with individual dimensions, please click on the button below:


Request for Quotation

48h-Express Service Also available in 48 h Express-Service



DST300 transmittance

DST300, spectral transmittance curve

DST300 at wavelength 400-700 nm


DST500 transmittance

DST500, typical transmittance

DST500 at wavelength 400-700 nm


DST700 transmittance

DST700, typical spectral transmittance

DST700 at wavelength 400-700 nm


Product Codes

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

Substrate Materials

Coating Definitions

(All specifications are given for an incidence angle of i = 45° and random polarization)

  • R:T = 50 : 50 (± 6%) for 450-650 nm
    R:T = 50 : 50 (± 10%) for 430-685 nm
  • Backside with broadband AR-coating
  • Standard thickness 1,00 mm (+/-0,1)
  • R:T = 30 : 70 (± 8%) for 450-650 nm
    R:T = 30 : 70 (± 10%) for 400-700 nm
  • Backside BBAR-coated
  • Standard thickness 1,00 mm (+/-0,1)


  • Depending on the material, thickness, and shape

Damage Threshold

  • Depending on laser beam diameter and power
    (Please send an inquiry if relevant)

Surface Quality

  • Better than 80-50 scratch & dig (MIL-0-13830A)
  • Different surface qualities per inquiry


  • up to approximately 630 mm x 810 mm (DST500)
    (Plate beamsplitter optics only. Cube-, polarizing-, non-polarizing-, or prism-splitters, and comparable components are not feasible with such large dimensions. Please discuss the size limitations 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. Also, please consider our "Notes on technical specifications".

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