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Beamsplitter plates for 45° angle of incidence

DST Series

Special Properties and Features

  • Neutral splitting of visible light sources, images, and laser beams
  • Broadband anti-reflection coating on the backside
  • Free of double image and phantom laser beam effects
  • Metal-free, fully dielectric coating construction
  • Low energy losses
  • Designed for random polarization
  • High precision
  • Large dimensions available (DST500)

Typical Applications

  • Reference measurement systems
  • Laser beamsplitters in optical benches
  • Semi-transparent mirrors for interferometers
  • Splitting or merging of optical beam paths
  • Sensor technology
  • Fiber Optic applications
  • Telecommunications
  • 3D imaging and machine vision
  • Photonics research
  • Beam splitter plates in optical instruments
  • Laser beam combiners
  • Optical measurement technology
  • Robotics and automation
  • Broadband divider mirrors for imaging applications

Related Products

  • SIR-Series
    (infrared-reflecting dichroic beam splitter, "hot mirror")
  • SHD-Series
    (dichroic infrared-transmitting beam splitter,
    "cold mirror")
  • ND filters
    (attenuation filters made of SCHOTT NG materials)
  • TDS Spy-Mirrors
    (partially transmitting "One-Way Mirror")



Beamsplitters are essential components in a wide array of optical systems and applications. Such components, also known as semi-transparent mirrors, are designed to divide an incident light ray into two or more, allowing them to follow different paths. With their excellent optical properties, our DST beamsplitter plates are typically used in numerous industries, including telecommunications, spectroscopy, microscopy, imaging systems, automation, laser technology, and scientific research.

The main function of a beam splitter plate is to split light into two separate beams with a defined intensity. Like optical mirrors, our beam splitters reflect a certain amount of incoming light with an angle of incidence of 45°, while the remaining light is transmitted in the 0° direction. This partial reflection and transmission characteristic is achieved by the principle of interference.

The multi-layer dielectric thin film, which is applied to the input side of our DST in a vacuum, determines the R/T values. Plate beam splitter splitting a laser beamA broadband anti-reflection coated backside prevents secondary reflections. Ghost images or phantom laser beams are virtually eliminated. In addition, the AR coating minimizes the losses typically caused by the reflective backside of a beam splitter. Unlike dichroic beamsplitters, such as our SIR filters or SHD mirrors, the DST splitter is neutral. It does not filter out specific spectra but splits visible light in a color-neutral manner.

In contrast to beamsplitters with metallic layers, which typically absorb a large portion of the incident energy, the losses of the DST are minimal because their dielectric layer system shows almost no absorption in the nominal wavelength range. As a result, the DST beamsplitters can also split laser beams of up to medium laser power. Many customers use them in reference measurement systems and optical benches. The coating design of our DST beam splitter plates ensures excellent durability and high abrasion resistance.

Our DST beamsplitters are designed for light with random polarization. When using a polarized light source or a laser, the actual R/T value may differ from the specifications in this datasheet, as we don't define them in terms of polarization accuracy. This does not preclude such applications. Often you can achieve the desired division by selecting a higher or lower existing division ratio. In such cases, the cost is drastically reduced when compared to a dedicated batch of custom beamsplitters, especially if only small quantities are needed.

If you require beamsplitters for polarized light, specific lasers, or a specific laser line, please contact us with information on the wavelength of your application, the required splitting, and other relevant details. In addition to our standard DST300, DST500, and DST700 series, we can coat beamsplitters with division ratios to individual specifications. Please use our inquiry form to request assistance, more information, or help in designing your custom coated beamsplitter.


How do I order the DST Plate beamsplitters?

We are not limited to standard optics with fixed dimensions. Our company specializes in rapid manufacturing and delivery of custom sized optics. We often ship our beamsplitters faster than distributors can ship their catalog items. This is possible in many cases, even for large quantities! You will usually receive our quote within a few minutes, provided you are in our time zone and there are no questions. Please select a beamsplitter from the table or press the RFQ button below to send your inquiry.




Customized optics within 48h 48-hour Express Manufacturing



DST300, spectral transmittance curve
Enlarge the DST300 curve

DST500, typical transmittance
Enlarge the DST500 curve

DST700, typical spectral transmittance
Enlarge the DST700 curve

Standard Thicknesses

Please click on a thickness to receive a quote:

Thickness (mm)


48h-Express manufacturing
R:T = 70 : 30
1,00 ±0,10
R:T = 50 : 50
1,00 ±0,10
R:T = 50 : 50
3,30 ±0,20 -
R:T = 30 : 70
1,00 ±0,10
Other thicknesses per inquiry.
The materials marked with "" are possible within 48–hour express manufacturing.


  • Up to max. 630 mm × 810 mm

Splitting ratios for a 45° angle of incidence

(All specifications are for unpolarized light.)

  • R/T = 70/30 (± 10 %) for 450–650 nm
  • R/T = 50/50 (± 6 %) for 450–650 nm,
    R/T = 50/50 (± 10 %) for 430–685 nm
  • R/T = 50/50 (± 10 %) for 450–650 nm
  • R/T = 30/70 (± 8 %) for 450–650 nm,
    R/T = 30/70 (± 10 %) for 400–700 nm
Different beam-splitting ratios, angles of incidence, and wavelengths are possible on demand.


Substrate Materials


  • Depending on the material and shape

Damage Threshold

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

Surface Quality

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

Other Specifications

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

Note: If you are searching for cube beamsplitters, beamsplitter prisms, non-polarizing cube beam splitters, beam splitter cubes for special wavelength ranges, or beam splitter penta-prisms, please send us a detailed inquiry with all specifications and requirements. Such kinds of optical components are always customized and require larger batch quantities.


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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Last update: April 22, 2024