Beamsplitters are optical components designed to divide an incident beam into transmitted and reflected components, forming an essential building block in countless optical systems.
Available as cemented cubes or thin plates, and in polarizing, non-polarizing, and unpolarized configurations, beamsplitters can be tailored to precise application requirements — whether that means preserving polarization state, generating defined orthogonal polarization outputs, or achieving a specific, non-standard split ratio. This breadth of design options allows beamsplitters to serve as a flexible, foundational component wherever a single input beam must be divided into two well-defined optical paths.
Properties
Optical beamsplitters are available in various designs such as plates, cubes and pentaprisms. Our selected suppliers can manufacture almost any design including coatings for light in the visible (400nm – 700nm), NIR (700nm – 1100nm) or IR (1100nm – 1600nm) range and AR coatings. Beamsplitter cubes offer the advantage that the reflected and transmitted light have the same optical path length and there is no beam offset of the transmitted light.
In addition, there are three different types of beam splitter polarization functions. These are called “unpolarized beamsplitter”, “non-polarizing beamsplitter” and “polarizing beamsplitter”. These are therefore differences in the way the polarization of the light to be split is handled.
If you are uncertain which beam splitter you need for your application, our short selection guide can help you or simply contact us instead.
Unpolarized Beamsplitters
Useful for natural, incoherent or unpolarized light. It is advised not to use these cubes in polarized optical systems.
For proper functioning, the incoming light should be one of the following:
– natural light
– circularly polarized
– 45° linearly polarized
This means that the s-polarized and p-polarized components should be roughly equal to each other in intensity. The outgoing beams are two partially polarized beams of approximately equal intensities.
Range of splitting ratios:
10/90 (R/T) to 90/10 (R/T) with T=(Ts+Tp)/2, R=(Rs+Rp)/2
Non-Polarizing Beamsplitters
These beamsplitters have minimal polarization sensitivity. Therefore they may be used in polarized optical systems.
Due to the metallic component of the hybrid coating, these beamsplitters are not intended for use with high power lasers since they show some absorption – typically about 8%.
Non‑polarizing beamsplitters are less sensitive to changes in angle of incidence than pure dielectric unpolarized beamsplitters.
Range of splitting ratios:
50/50 (R/T) with
|Ts-Tp|<5-15%; |Rs-Rp|<5-15% dependant on bandwidth
Polarizing Beamsplitters
These beamsplitters separate the “s” and “p” polarization components of a light beam. These two polarization components are reflected (“s”) and transmitted (“p”) respectively. Thus, both components are well separated (90°) and available for further use.
When non-polarized light is normally incident upon the entrance face, it is separated into two polarized beams, emerging through two adjacent faces in perpendicular directions and polarized orthogonally to each other.
When linearly polarized light is incident, it is similarly divided into two beams in a ratio depending upon the orientation of the polarization of the incident light beam.
Range of splitting ratios: Typically Tp:Ts > 1000:1
Unpolarized Beamsplitters
Useful for natural, incoherent or unpolarized light. It is advised not to use these cubes in polarized optical systems.
For proper functioning, the incoming light should be one of the following:
– natural light
– circularly polarized
– 45° linearly polarized
This means that the s-polarized and p-polarized components should be roughly equal to each other in intensity. The outgoing beams are two partially polarized beams of approximately equal intensities.
Range of splitting ratios:
10/90 (R/T) to 90/10 (R/T) with T=(Ts+Tp)/2, R=(Rs+Rp)/2
Non-Polarizing Beamsplitters
These beamsplitters have minimal polarization sensitivity. Therefore they may be used in polarized optical systems.
Due to the metallic component of the hybrid coating, these beamsplitters are not intended for use with high power lasers since they show some absorption – typically about 8%.
Non‑polarizing beamsplitters are less sensitive to changes in angle of incidence than pure dielectric unpolarized beamsplitters.
Range of splitting ratios:
50/50 (R/T) with
|Ts-Tp|<5-15%; |Rs-Rp|<5-15% dependant on bandwidth
Polarizing Beamsplitters
These beamsplitters separate the “s” and “p” polarization components of a light beam. These two polarization components are reflected (“s”) and transmitted (“p”) respectively. Thus, both components are well separated (90°) and available for further use.
When non-polarized light is normally incident upon the entrance face, it is separated into two polarized beams, emerging through two adjacent faces in perpendicular directions and polarized orthogonally to each other.
When linearly polarized light is incident, it is similarly divided into two beams in a ratio depending upon the orientation of the polarization of the incident light beam.
Range of splitting ratios: Typically Tp:Ts > 1000:1
Applications
Industrial Machine Vision and Image Processing
Inject illumination light into a camera’s object path to produce coaxial illumination for shadow-free inspection of flat surfaces.
Divide one optical path into two to achieve stereo vision for 3D measurements and depth information.
Split wavelength ranges using a dichroic beamsplitter for multispectral imaging, for example combined VIS and SWIR imaging.
Spectroscopy and Analytical Instrumentation
Split incoming light between a reference detector and a sample measurement path, supporting accurate relative intensity measurements in absorption, reflectance, and Raman spectroscopy setups.
Microscopy and Fluorescence Imaging
Enable simultaneous illumination and detection paths in fluorescence, confocal, and polarization-sensitive microscopy systems, directing excitation light toward the sample while transmitting emitted light to the detector.
Laser System Beam Sampling and Power Monitoring
Divert a defined fraction of a laser beam to a photodetector for real-time power monitoring or feedback control, while the majority of the beam continues undisturbed along the primary path.
Optical Isolation and Laser Protection
Support the construction of optical isolators when combined with waveplates, preventing back-reflected light from destabilizing sensitive laser cavities or amplifier systems.
Optical Communication and Signal Distribution
Divide optical signals across multiple detection, processing, or transmission channels in free-space communication systems, supporting redundancy or parallel signal paths.
Holography and Interference Pattern Generation
Combine or divide coherent beams with controlled amplitude or polarization ratios to generate stable interference patterns for holographic recording and diffractive optical applications.
Interferometry
Divide a coherent source into reference and measurement arms with well-defined amplitude or polarization characteristics, supporting precise phase and displacement measurements in a range of interferometer configurations.
Camera and Viewfinder Optical Systems
Divert a portion of incoming light to auxiliary sensors — such as autofocus or metering detectors — while preserving the primary image path for the main imaging sensor.
Why Choose Our Beamsplitters
Wherever precisely defined beam division is essential, our beamsplitters deliver an angularly accurate, high-quality solution — with beam deviation as low as 5 arcseconds and surface figures up to λ/10. Available in cube and plate designs in polarizing, non-polarizing, and unpolarized configurations to meet your system’s exact optical requirements.
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