Beam Shapers: Classifications And Applications

Beam shapers are the optical components that are designed to change the appearance of laser beams into radiance distributions which is required. There are a lot of laser beams that naturally exhibit a single-mode beam distribution pattern, known as the Gaussian distribution pattern. This distribution features maximum irradiance at the center, which gradually diminishes towards the edges. Given that this natural beam pattern doesn’t have sharp edges, in theory, the beam profile never achieves zero irradiance. This characteristic results in a notable energy loss in the Gaussian beam when a process has a certain threshold.

A beam shaper addresses this by reforming the input beam to attain a new distribution pattern with sharp edges and uniform irradiance, minimizing energy losses and rectifying the irregularities of the input beam.

Types Of Beam Shapers

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Beam shapers vary based on their properties and principles of operation. Some operate using refraction, while others employ the diffractive principle.  Some are diffusers that shape the light by overlaying the beam on itself and scrambling the phase, while others are analytical beam shapers that shape the light while maintaining a smooth phase.  The primary beam shaper types include Micro-lens Arrays, Broadband Diffusers, Diffractive Diffusers, and Top Hat Beam Shapers.

Micro-Lens Arrays, Broadband Diffusers

Micro-lens Arrays (MLAs) and Broadband Diffusers both are diffusers that operate on the refractive principle. However, they possess distinct characteristics. MLAs ensure irradiance uniformity in designated areas when handling polychromatic or incoherent input beams. They may, however, have order artifacts with coherent illumination. Broadband diffusers, conversely, utilize randomized lenslet profiles, achieving a more uniform irradiance and fewer order artifacts. Diffractive diffusers are a third type of diffuser that can shape the input beam into various geometrical patterns, including circles and arbitrary shapes.

Diffractive Diffusers And Top Hat Beam Shapers 

Diffractive Diffusers and Top Hat Beam Shapers harness the diffractive principle to achieve beam profiles with sharp edges and consistent irradiance. Diffractive diffusers not only introduce phase variations to the beam but can also create a randomized pattern by scrambling the phase, potentially resulting in speckles on the input laser coherence. Top Hat beam shapers incorporate diffractive optical elements (DOEs) to modify the wave nature of the beam, achieving a predetermined spot geometry and a consistent flat-top irradiance profile. These are particularly adept at transforming coherent single-mode light beams while preserving phase integrity.

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Diffractive Beam Shaping 

These beam shapers use diffraction in lieu of refraction. It uses technology to shape the specific irradiance. The diffractive elements use a particular etching process. It does it to create specific nanostructures in one substrate—these designers’ wavelength bank on the zone spacing, height and other functions. 

Therefore, using one element in the designing wavelength is done to avoid errors in the performance. If you compare it to the refractive beam shaping variant, they bank on the divergence, alignment, and beam position. 

The advantage that you have with the help of diffractive beam shaping is that they are more fitting in space-related setups. This is because they comprise a single element and not the refractive lens.

The Laser Beam Integrators

The LBI is also called the homogenizer. It is made up of different lenses. They divide the beams into a combination of smaller beams. The lens or one focusing element follows it. It superimposes the beamlets at the plane of targets. You can use them with both incoherent and coherent laser light sources.

Most of these integrators are applied to create the flat top profile (homogenized) from the incident Gaussian beams. These homogenizers usually face problems from the fluctuation of random irritants—the selection between the deflation of imaging beam integrators and the diffraction bank on the number of fresnels. 

Circularazing Beams With The Cylinder Lenses

Another variant of laser beam shaping is the Circularizing Beams. It converges the profile of different shapes to a circular shape. The laser diodes with zero collimating optics possess various angles of divergence in both the x and y axes. Because of the rectangular shape and the active region of the diode, it results in the form of oblong beam shapes. 

Just like the standard lenses ( spherical), these lenses (cylindrical) also use a curved surface so that they converge and diverse light. The cylinder lenses do not negatively impact the light perpendicularly. The property of the lens makes them effective for forming sheets with laser light. 

Beam Shaping Optics solution for laser-wielding 

This section discusses some of the most important and unique diffracted diffuser custom solutions. They are developed for the process of the laser welding process, which includes:

1. T-Shaper 

The particular shape is quite different. They possess one  hot spot in the middle. It allows for scanning the shape and simultaneously weld the seam  in the joining of the butt end.

C-Shaper 

The particular diffuser develops the width or depth ratio, whereas the wielding eliminates the hot cracking by offering the bubbles a place to evade the welding area.

Brazing Diffuser 

This unique diffuser disintegrates two leading dots and the other spot in the center. The particular distribution is used for melting a brazing wire between the two galvanized plates. It performs the function while preheating and cleaning both the sides.

The diffractive optical elements are one of the most accurate solutions for beam shaping. The best thing is that they are one beam-shaping solution with the angular tolerance. The most noteworthy specifics of the technology are that they are a lightweight element with superb beam shaping abilities.. The quality of the DOEs is indeed an advantage. 

Applications Of Beam Shapers

Beam shapers have a myriad of applications. In material processing tasks such as laser scribing and welding, they facilitate the achievement of precise and uniform laser irradiance spots. They’re also instrumental in cutting materials such as glass or metal.

In ablation processes crucial to electronics and solar panel production, beam shapers find extensive use. Medical applications, too, are significant, with beam shapers playing pivotal roles in aesthetic procedures such as body contouring, tattoo removal, and skin resurfacing. In flow cytometry, they aid in examining particles flowing in liquids when subjected to a laser beam. In laser projection applications, beam shapers contribute to micro-display uniformity.

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