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Optical 45°-Beamsplitters

Special Characteristics

  • Largely color neutral splitting of incident light, images and lasers
  • Rear side anti-reflection coated
  • Strong suppression of ghost images (ghosting)
  • Low-loss dielectric optical coating design
  • Non-metallic thin film layers
  • Made for random polarization
  • High optical quality
  • Very large dimensions available (DST500)

Typical Applications

  • Efficient division of beams, lasers and images
  • Optical reference measurement systems
  • Semi-transparent optics for interferometer systems
  • Laser beamsplitter for up to medium beam powers
  • Sensor technology
  • Fiber optics
  • Teleprompter-mirrors
  • Photonics applications
  • Laser beam-combiners
  • Beamsplitter plate in optical measuring instruments
  • LED-reference measurement technology
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48h-Express Service Also available in 48 h Express-Service

DST optical beamsplitters split incoming light into a transmission and a reflection component, so incident light, an image or a laser beam is partially reflected, as by a mirror, and partially transmitted, as through a window.

Plate beamsplitters used as laser beam dividerThe input side of the beamsplitter plates has a dielectric thin film coating which determines the division ratio. On the backside there is a broadband anti-reflection coating that prevents secondary reflections. By this AR-coating, so-called ghost images are nearly completely suppressed and losses otherwise caused by reflections from the glass back side cannot occur.

Unlike dichroic beamsplitter products, such as our SIR hot-mirror or SHD cold-mirrors, our DST beamsplitters operate non-dichroic. They do not separate different optical spectra from each other, but rather split light rays in the visible spectrum to a large extent color-neutral. A non-metallic construction ensures good durability and abrasion resistance. The dielectric layer system of the semi-transparent mirrors only has a very low absorption in the nominal wavelength range. Hence, very little energy is lost by absorption effects, as typical for metal based beamsplitters. As substrate materials for the DST series we use iron-reduced glasses, resulting in a low-loss design, which also allows the beamsplitters to be used in laser applications with small to medium laser beam power.

Flat laser beam dividing opticsAll DST beamsplitters are designed for unpolarized light. The polarization directions of all photons in an unpolarized light beam are uniformly distributed which is not the case for polarized light. So, when used with polarized light or a polarized laser, the splitting ratios of the DST-beamsplitters may vary from the specifications given. The division-ratios in this data-sheet are defined only for random polarization. This means, all DST beamsplitters are undefined with respect to polarization behavior or polarization effects. This, however, does not exclude applications with polarized light. Often, the desired splitting ratio can be achieved by choosing an existing higher or lower nominal division ratio for random polarized light and costs can be drastically reduced compared to a customer-specific coating batch. If you search for a beamsplitter plate for polarized light or a polarized laser, please contact us. In the case of special requirements for the polarization properties and at a sufficient quantity of production in most instances we are capable of fabricating customer-specific polarization-optimized beamsplitter optics.

In addition to our standard optical plate beamsplitters DST300, DST500 and DST700, the division ratios can be adapted to custom specifications. From a certain batch size upwards, we can also produce cube beam splitters, beam splitter penta-prisms, NIR dividers and high-performance beam splitters. Design and manufacturing of polarizing beam splitter cube optics, as well as polarization obtaining beam splitters can also be realized. Such special optics are always manufactured according to customer's requirements. They are therefore not listed in detail in our website. So if you search for such optics, please go to our inquiry form to request a quote for any kind of specialty beamsplitters.


How can I purchase the DST beamsplitters?

We are specialized in rapid manufacturing and delivery of our DST-beamsplitters with custom dimensions. Usually, we deliver custom dimensions just as fast or even faster than stock items with fixed dimensions are used to be delivered by the competition. This also and particularly applies to large production quantities. If you are in our time zone and there are no queries, you normally will receive our quotation within a few minutes. Our goal is that you get what you need, so that the beam splitter perfectly fits in your application and not just in a shopping cart.

To request an offer for one of our DST beamsplitters with freely defined dimensions, please click on the button below.


Request for Quotation



DST300, transmittance

DST300, spectral transmittance curve for visible wavelengths

DST300 at wavelength 400-700 nm


DST500, transmittance

DST500, typical transmittance for visible wavelengths

DST500 at wavelength 400-700 nm


DST700, transmittance

DST700, 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

(Incidence angle i = 45° / random polarization)

  • R : T = 70 : 30 (± 10%) at wavelengths
    of 450-650 nm
    (Typical conditions for laser use on request)
  • 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 laser use on request)
  • Rear side with broadband 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 laser use on request)
  • Rear side with broadband AR-coating
  • 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 use on request)
  • Rear side BBAR-coated
  • Stock tk. 1,00 mm (+/-0,1)


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

Damage Threshold

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

Surface Quality

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


  • up to approximately 630 mm x 810 mm
    (Flat beam splitter optics only. Cube-, polarizing-, non-polarizing- or prism-beam splitters, etc. are not feasible with 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"