Surface Coating / Alfa Chemistry

Customized Dielectric Beamsplitter Coating


The term "beam splitter" refers to a coating that divides a light beam into multiple beams. It divides light of a specific wavelength into two distinct beams with incidence angles of approximately 45 degrees to the normal. This is a typical optical component. Coatings for dielectric beam splitters are non-absorbing and have a high energy throughput. 30/70, 50/50, and 70/30 are common dielectric beam splitter coatings. Metal beam splitters are often far more broad than their dielectric counterparts, and can cover a wider range of wavelengths. Beam splitter coatings can also be produced out of transmission metals like inconel and chromium.

Alfa Chemistry offers custom coating services for non-absorbing dielectric beam splitters. We coat several types of optical materials, such as glass, plastics, and semiconductor materials, with metallic and dielectric beam splitter coatings, allowing for better control of the reflectance to transmission ratio of the light source being divided. Please contact us to discuss your specific optical needs. For special application needs, we will meet your custom specifications.

Alfa Chemistry Customized Optical Coating

Plate Beamsplitter

A plate beam splitter is a thin optical glass plate with one type of dielectric coating on each side. It offers a number of advantages: 1) Because it does not contain any optical glue that absorbs light energy, it can sustain higher levels of laser power without being damaged. 2) When compared to cubic beam splitters, it is smaller and lighter. Alfa Chemistry offers the following coating options.

  • 45° 50/50 Plate Beamsplitter

From 425 to 650nm, this coating is designed to transmit 50% and reflect 50% minus 10% at a 45-degree incidence angle.

  • 45° 70/30 Plate Beamsplitter

At a 45-degree incidence angle, this coating reflects 70% and transmits 30% (10%) of the light from 450 to 650nm.

  • 45° 30/70 Plate Beamsplitter

At 45 degrees incidence, this coating transmits 70% and reflects 30% (10%) of the light in the 450-650 nm band.

  • Unpolarized Plate Beamsplitter

When the polarization characteristics of the incident laser light must be preserved in both the reflected and transmitted beams, this coating is utilized. They can also be employed to achieve a 50/50 split of laser energy within tolerances, independent of incident beam polarization. Other flat beam splitter coatings do not have this capability.

Plate Beamsplitter

Cube Beamsplitters

Cube beam splitters are strong beam splitters made up of two identical right-angle prisms that are perfect for beam stacking. On the mirror surface, we apply a somewhat reflective layer. Because the coating is contained inside the cube's body, it is extremely resistant to aging. When dividing light into component polarizations across a broad spectrum, the cube beam splitter comes in handy. Alfa Chemistry offers the following coating options. Your decision should be based on the intended use.

  • Hybrid Partial Reflectance Coating

The advantages of metal and dielectric are combined in this hybrid metal-dielectric coating to provide a moderately absorbing beam splitter with low polarization sensitivity. To maximize polarization separation, 45° cubic polarization beam splitters often use a higher refractive index glass.

  • All-dielectric non-polarizing coatings

These coatings are employed in situations where polarization effects must be maintained to a minimum. They are designed for high performance at certain wavelengths. Their absorption is negligible since they are totally dielectric.

The 45° non-polarized hybrid cubic beam splitter is an example. In the 475 to 625 nm band, the coating has an average transmittance of 45 percent and a reflectance of 45 percent for "S" and "P" polarization.

Cube Beamsplitters

Our products and services are for research use only and cannot be used for any clinical purpose.

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