The beam splitter is useful for generating several output beams by splitting an incoming optical laser beam. To split a single input laser beam, beam splitters consist of diffractive optical elements or DOEs. The interesting thing about this beam splitting is that both the input beam and output beams have the same characteristics. The only characteristics that differ in the output beams are power and the angle of propagation. However, there are different kinds of beam splitters that split the input beam differently and display slightly different outcomes. In this article, we will mention three major kinds of beam splitters and discuss their characteristics.
Beam Splitters & Their Characteristics
- First of all, we will introduce you to the plate beam splitters that split the input beam into two output beams, the transmitted beam and a reflected beam. The angle of incidence of the single input beam determines the angle of propagation and the direction of these output beams. In general, the angle between these two output beams is 90 degrees. These plate beam splitters do not change the beam size and divergence of the input beam, maintaining them in the output.
- Another kind of beam splitter that has significant medical and industrial applications is the Microlens array. The setup for this beam splitter involves lenslets or a succession of small lenses where every lens has the same size and radius of curvature. Microlens arrays generate several smaller output beams by clipping the input laser beam, thus the MLA does not maintain the input beam characteristics in the output beams . The output beams coming out from each lens meet each other at the focal plane.
- When it comes to a beam splitter’s versatility and efficiency, diffractive beam splitters stay at the top. Diffractive beam splitters are more efficient than Microlens arrays and plate beam splitters. While the working principle of the earlier-mentioned beam splitters is the optical refraction or reflection principles, diffractive beam splitters exploit the wave nature of the input laser beam by using the principle of light diffraction. Diffractive beam splitters display the interference effect while transmitting the output beams. These beam splitters can create different geometrical patterns during beam splitting. Therefore, one can customize a diffractive beam splitter to generate a particular beam pattern. These beam splitters also offer the flexibility of determining the angular orientation and spatial separation among the output laser beams.
Applications
Diffractive beam splitters are highly useful beam splitters and have varied applications in the academic, medical, and industrial fields. A notable application of a multi-spot diffractive beam splitter is aesthetic skin treatment. In this beam-splitting process, an array of output beams is focused to the skin plane creating an irradiance pattern with a much greater area compared to a single beam, increasing treatment speed by a significant factor. Some other useful industrial applications of beam splitters are laser scribing, 3D sensors, laser dicing, and fiber optics. Microlens arrays are useful for 3-D sensing, imaging, and telecommunications, whereas plate beam splitters have a significant application in fiber optics.
