What are Beamsplitters & Windows?
Beamsplitters
The primary function of a beamsplitter is to separate a single beam of light into two parts, one reflected and one transmitted. The incident light is split at the surface which is usually set at some angle so the reflected and transmitted beams are separated. Any metal layer that forms a partially reflective mirror can serve as a beamsplitter, and many under the “plate” category are no more sophisticated than that.
Windows
An optical window is a transparent optical element that allows light to pass through with minimal reflection and absorption. Windows are typically used to protect optical instruments and sensors from the external environment while maintaining the integrity of the optical path by introducing minimal wavefront distortion. Our windows and window coatings are designed to withstand environmental conditions such as temperature changes, humidity, abrasion, and mechanical stress, ensuring that the performance of the optical system remains unaffected. Optical windows can be made from various materials, such as glass, fused silica, or crystals, depending on the specific requirements of the application, such as the wavelength range and environmental durability needed.
Types of Beamsplitters & Windows
Beamsplitters
In many scientific and electronics applications, it is necessary to split an incident beam into two spectral bands – one transmitted, the other reflected – and maintain an extremely sharp slope of transition between the bands. These are called dichroic beamsplitters. And since they utilize dielectric materials, they carry the advantage of having negligible optical loss compared to absorptive types of color separators.
Broadband (KBr, Csl) Beamsplitters
Potassium Bromide (KBr) and Cesium Iodide (CsI) are materials which can be used to produce windows and beamsplitters which transmit from the visible to far infrared. Omega Optical has proprietary processes for polishing and coating these hygroscopic crystals.
Plate Beamsplitters
Our broadband linear plate beamsplitters are a type of beamsplitter used in many life sciences, imaging, or laser applications, as well as in the entertainment and design industry. The coating is nearly wavelength independent across the visible spectrum.
Polka-Dot Beamsplitters
Provide a near constant reflection to transmission ratio from 250nm to over 2.0µm with minimal angle sensitivity. In production, micron-scale “polka-dots” of aluminum are deposited on the substrate.
Other Beamsplitters
Inquire about custom beamsplitter substrates and coatings.
Resources
Other Resources
Questions About Beamsplitters & Windows
What are good applications for KBr?
- Beamsplitters in commercial FT-IR instruments
- Coated VIS to LWIR Windows
- Liquid and gas cell windows
- Un-cooled infrared detector windows
- When protectively coated, purged compartment windows
What is Potassium Bromide (KBr)?
KBr is the most commonly used material for commercial infrared spectroscopy. It has a relatively low refractive index which permits the design of very high quality beamsplitters. Impurities in the single crystal KBr ingots are usually caused by the atmosphere in which the ingot is grown. Although the impurity bands are weak they can cause problems because they are very narrow (<6 cm-1). Since FT-IR instruments are unable to ratio these bands perfectly, it is important to use only the purest KBr material available for use in beamsplitters. In good quality KBr the level of impurity bands is less than 1% for a typical beamsplitter thickness.