Just like what the name indicates, a beam splitter is an optical device designed to split an incidental light into two. Of course, when this happens, each of these light sources will have reduced power compared to the original and single light version.
Beam Splitter Constructions
So, how does a beam splitter look like? Well, in its most common form, beam splitters are usually in the shape of a cube. It is made out of two triangular glass prisms.
The hypotenuse surface of the cube is coated whereas the two prisms are glued together using a polyester proxy. What people usually do is let the light transmit through the coated prism. The purpose of doing this is to prevent the polyester proxy from being destroyed.
Meanwhile, we also have the plate beam splitters. These types of beam splitters are thin and flat. There is coating in the first surface of the substrate. Most of the time, plate beam splitters have anti-reflection coating as to remove unwanted Fresnel reflections.
Now, let’s look at the pros and cons of using these two beam splitters:
Cube Beam Splitters
The great thing about cube beam splitters is that they are easy to integrate with 0° AOI, there’s no beam shift, and it has equally reflected and transmitted optical path lengths. Apart from that, it can also shorten the path of a system.
On the downside, cube beam splitters have heavy solid glass construction. It can also be more difficult to make if you are after large sizes.
Plate Beam Splitters
Meanwhile, a lot of people say that plate beam splitters are most convenient because they are inexpensive and easy to manufacture in large sizes compared to the cube beam splitter. What’s more is that it is lightweight.
But nothing in this world is perfect. Despite the convenience that plate beam splitters bring, unfortunately, they may require additional alignment time for 45° AOI. The transmitted and reflected paths are also different length.
We hope that helped you decide on the kind of beam splitter construction that will be the best for you. Now, it’s time to move forward to the different types of beam splitters. In this article, we are going to talk about polarizing beam splitters and non-polarizing beam splitters.
Polarizing Beam Splitters
The main purpose of these beam splitters is to split incidental light into S-polarized and transmitted P-polarized beams. You can split unpolarized light at a 50/50 ratio.
Non-polarizing Beam Splitters
Meanwhile, non-polarizing beam splitters specialize on splitting light into specific R/T ratio. The goal is to do this while maintaining the original polarization state of the incidental light. This type of beam splitter is most useful for people who wants to maintain polarization in polarized light-inducing applications.
It’s really quite wonderful what these things can do. While a lot of people are now using beam splitters, it is hard to deny that this type of technology still needs further work and research. There is quite a limited device for so many uses. If you need one that is customized for your needs, you may want to check out https://www.evaporatedcoatings.com/beamsplitters/.