Products/Beam Shaping/Top-Hat Beam Shapers

Beam Shaping · 2D Top-Hat

Top-Hat Beam Shapers

Q: Which lasers does it work with?

Any single-mode source (M² < 1.5, higher on request), from deep-UV to near-IR, femtosecond to continuous-wave, low power up to 50 kW+. Send us your wavelength, power/regime, M² and input beam and we confirm fit.

Q: Why does the focal plane matter so much?

A conventional flat-top is shaped for a single plane: the profile is at its best right at focus and softens as you move away from it. That's the trade for its flexibility and efficiency. If your process can't hold focus tightly, the depth-of-field-engineered 3D Top-Hat is the better fit.

Q: How do I integrate it?

We recommend a collimated beam with a focusing lens; the shaper can sit in a parallel/Z-folded, folded, or scanner (F-Theta) path. It's all-reflective and works at 45°, so it often just replaces an existing fold mirror. It's insensitive to lateral alignment, though rotation is fixed by the structure.

We shape a homogeneous flat-top for single-mode lasers, sized and shaped to your process. It converts a Gaussian into a uniform plateau from 1.5× to 10× the spot, round, square or rectangular, at exceptional efficiency. When you can hit the focal plane accurately, it’s the most flexible and efficient flat-top we make.

Discuss your challenge

Round · square · rectangular 1.5–10× Gaussian spot >90–95% efficiency

3D surface plot of a flat-top beam: a uniform plateau of intensity with steep edges

The outcome

Uniform energy, exactly the size and shape you need

A raw Gaussian puts too much energy in the centre and not enough at the edges, so ablation, cutting and surface processes come out uneven. A flat-top replaces that peak with a homogeneous plateau, so every part of the spot does the same work. Ours comes shaped to your geometry as standard, round, square, rectangular or custom, anywhere from 1.5× to 10× the Gaussian spot, and delivers that at >90–95% efficiency: almost all your laser power ends up in the useful profile.

Why this flat-top

Flexible, efficient, all-reflective

Any size, any shape

A plateau anywhere from 1.5× to 10× the Gaussian spot diameter, in round, square, rectangular or custom geometry, built to your process rather than pulled from a catalogue.

Exceptional efficiency

>90% at 1.5× and >95% from 2× to 10× the spot, with <5% plateau non-uniformity (ISO 13694) and side modes under 1.5%. Almost all the power lands in the useful profile.

All lasers, all power

All-reflective, micro-structured mirror optics: deep-UV to near-IR, femto to CW, to 50 kW+. They stay stable at power, where transmissive optics drift under thermal lensing.

Highlight

Optimized to your M²

Beam quality isn’t an afterthought here: every shaper is designed against your laser’s actual M², not a generic ideal M²=1.0. Matching it to your laser lets us push homogeneity to the best your system can deliver. Send us your M² and we design around it.

We individualize flat-top size, shape and wavelength to your beam and system as standard.

Which top-hat is right for you?

This 2D Top-Hat, or the 3D Top-Hat?

Both turn a Gaussian into a flat-top. The difference is where they win: maximum flexibility at focus, or maximum stability through depth.

This page

Top-Hat Beam Shaper

Best when you can hit the focal plane. Free choice of size (1.5–10×) and shape (round, square, rectangular), at the highest efficiency (>90–95%). The flat-top is optimized right at focus, so your process needs good alignment and an accurately placed focal plane to get the full benefit.

Any size 1.5–10× the Gaussian spot
Round, square, rectangular or custom shape
Highest efficiency, >90–95%
Performs best in the focal plane

3D Top-Hat

Best when the process moves through depth. An EDOF-engineered flat-top that holds its shape across an extended axial range: a wider, more forgiving process window on the line. Fixed at a round 1.8×-diffraction-limited spot in exchange for that depth stability.

Stable across an extended depth of focus
Round profile, ~1.8× diffraction-limited
Resistant to focus shifts & alignment on the line
For production where the focus can’t be held exactly

View 3D Top-Hat →

Not sure which fits? Send us your laser, target profile and how tightly you can hold focus. We’ll recommend the right one.

Choose your shape

Round, square or rectangular: at any size

The plateau geometry is a design choice, and it scales with your target size. These are simulated intensity profiles: red is peak intensity, blue the falling edge. At a small 1.5× plateau the edge (and its diffraction side-lobes) take up a larger share of the spot; scale up to 2–10× and the same edge becomes a thin border around a broad flat plateau.

SquareCircularRect. 1.5× $Simulated 1.5x square flat-top intensity profile — a small red plateau with visible diffraction side-lobes around it$ $Simulated 1.5x circular flat-top intensity profile — a small red disc with faint diffraction rings$

2–10×

Simulated flat-top profiles from the Top-Hat Shaper datasheet. Any shape, from a tight 1.5× to a broad 10× plateau.

Other shapes and aspect ratios on request. Tell us the footprint your process needs and we design the profile around it.

Understanding the profile

Same edge, bigger plateau: why size sets the quality

Line plot of normalized intensity vs position: a narrow blue Gaussian, a slightly wider orange 1.5x flat-top, and a broad green 5x flat-top. Both flat-tops share the same edge slope as the Gaussian, but the 5x has a much wider flat plateau — A Gaussian (blue) and two flat-tops built from the same spot: 1.5× (orange) and 5× (green). Both flat-tops rise and fall on the **same edge** as the Gaussian; only the plateau between them grows.

Think of a flat-top as a Gaussian cut through the middle, with a flat plateau inserted between the two halves. The rising and falling edges keep the Gaussian’s shape, because that edge is set by your optical system, and ultimately by the diffraction limit. Nobody can make it steeper; we insert the plateau, we don’t change the flanks.

So the edge width stays essentially fixed, while the plateau is whatever size you ask for. That’s why size sets the quality: at a large 5× plateau the fixed edge is only a thin border around a broad flat-top, but at a tight 1.5× the same edge takes up most of the spot and there’s barely any flat region left.

The rule of thumb

You can’t turn a 20 µm Gaussian into a clean 20 µm flat-top: the fixed edges would be as wide as the spot, leaving no plateau. To get a well-defined flat-top, either enlarge the input beam or shorten the focal length so the plateau is comfortably larger than the edge. Tell us your target size and we’ll tell you the beam or focal length it needs.

Fit check

Will it fit your setup?

Every flat-top is matched to your laser, target profile and process. We design against the parameters below: send them and we confirm fit for your exact configuration.

Laser

all wavelengths — deep-UV to near-IR (266 nm to 1064/1030 nm and beyond)

Beam quality

single-mode, M² < 1.5 (higher on request)

Input beam Ø

customized ±5%; up to 16 mm (AOI 45°)

Power / regime

femto to CW · low power to 50 kW+

Target flat-top

size (1.5–10×) & shape (round / square / rect)

Focus

process should sit at the focal plane — for depth tolerance, see 3D Top-Hat

Recommended setup: integrate into a collimated beam with a focusing lens. The flat-top is optimized at the focal plane; for setups without a lens, contact us for analysis.

Technical evidence

Specifications

Parameter	Characteristic
Flat-top geometry
Flat-top size	1.5× – 10× of Gaussian spot diameter (1/e²)
Shape	Round, square, rectangular or custom
Efficiency	>90% (1.5× Gaussian spot) \| >95% (2–10× Gaussian spot)
Homogeneity	<5% plateau uniformity (ISO 13694:2018)
Strongest side modes	<1.5%
Depth of focus	Performs best at the focal plane — accurate focus positioning required. For a flat-top that stays stable across depth, see the 3D Top-Hat.
Input beam requirements
Input beam	M² < 1.5; higher on request
Input beam diameter	Customized for beam diameter ±5%; max diameter 16 mm (AOI = 45°)
Wavelengths	1064/1030 nm; 532/515 nm; 450 nm; 355/343 nm; 266 nm; others on request
Clear aperture	≥ 2× beam diameter (1/e²)
Integration
Alignment	Lateral alignment required; rotation not possible (for rotated structures, contact us)
Setup	Recommended: integrate into a collimated beam with a focusing lens. For setups without a lens, contact us for analysis.
Further specs
Material	Micro-structured dielectric HR coating on fused silica substrate
Reflectivity	>99.9% @ 1064/1032 nm; 532/515 nm; 355/343 nm — >99.8% @ 266 nm
Dimensions	Ø25 mm/1″ and Ø50 mm/2″. Other dimensions on request.

Datasheet v1.3. Values refer to a single-mode input and aberration-free optical system; system aberrations and beam quality may influence the achieved results. Exact performance confirmed per configuration.

Integration

It mounts like a mirror. It aligns like an optic.

Beam path with the shaper and a folding mirror before the focusing lens, in a Z-folded arrangement.

Parallel / Z-folded

Shaper with a folding mirror before the lens: any distance to the lens, focal length f to the part.

Beam path with the shaper at 45 degrees folding the beam into the focusing lens, replacing a mirror.

Folded: replaces a mirror

Shaper at 45° folds the beam straight into the lens: takes the place of a deflection mirror already there.

Scanner

Shaper ahead of the scanner and F-Theta lens: flat-top processing for scanned applications.

Other configurations and angles-of-incidence (AOI) available. Tell us your beam path and we’ll propose the cleanest integration.

Applications

Where it's used

Fine structuring, high precision

Micromachining & Precision Structuring

Sharper features and a wider, more forgiving process window.

Explore → One optic, no active focus

Marking & Traceability

Consistent mark quality on curved or height-varying parts — no f-Theta, no active focus.

Explore →

FAQ

Frequently asked questions

What’s the difference between the 2D and the 3D Top-Hat Shaper?

This 2D Top-Hat Shaper gives you free choice of size (1.5–10×) and shape (round, square, rectangular) at the highest efficiency, but it’s optimized right at the focal plane, so your process needs good alignment and an accurately placed focus. The 3D Top-Hat is EDOF-engineered to hold a round ~1.8× flat-top stable across an extended depth of focus: the right choice when your process moves through depth or you can’t hold focus exactly.

What size and shape can I get?

The plateau can be anywhere from 1.5× to 10× the Gaussian spot diameter, in round, square, rectangular or custom geometry. Tell us the footprint your process needs and we design the profile around it.

I have a 20 µm Gaussian spot. Can I get a 20 µm flat-top?

Not as a same-size, crisp-edged flat-top. The edge of a flat-top can never be perfectly sharp: its steepness is limited by your optical system and, ultimately, by the diffraction limit (the optical resolution). If the plateau is the same size as the original spot, the edges end up as wide as the spot itself and there’s essentially no flat region left. To fix that, make the flat-top comfortably larger than that edge width: enlarge the input beam or shorten the focal length, so the plateau is much wider than the diffraction-limited edge. Send us your target size and we’ll tell you the beam diameter or focal length it needs.

How efficient is it?

Better than 90% at 1.5× the spot, and better than 95% from 2× to 10×, with less than 5% plateau non-uniformity (ISO 13694) and side modes under 1.5%. Almost all your laser power ends up in the useful profile.

Does my beam quality (M²) matter?

Yes, and we use it to your advantage. Every shaper is optimized against your laser’s actual M² rather than an idealized beam, letting us push plateau homogeneity to the best your system can achieve. We handle M² < 1.5 as standard, and higher on request. Just send us your measured value.

Which lasers does it work with?

Any single-mode source (M² < 1.5, higher on request), from deep-UV to near-IR, femtosecond to continuous-wave, low power up to 50 kW+. Send us your wavelength, power/regime, M² and input beam and we confirm fit.

Why does the focal plane matter so much?

A conventional flat-top is shaped for a single plane: the profile is at its best right at focus and softens as you move away from it. That’s the trade for its flexibility and efficiency. If your process can’t hold focus tightly, the depth-of-field-engineered 3D Top-Hat is the better fit.

How do I integrate it?

We recommend a collimated beam with a focusing lens; the shaper can sit in a parallel/Z-folded, folded, or scanner (F-Theta) path. It’s all-reflective and works at 45°, so it often just replaces an existing fold mirror. It’s insensitive to lateral alignment, though rotation is fixed by the structure.

See all questions

Is a flat-top right for your process?

Send us your laser, target profile and how tightly you can hold focus. We'll confirm the right shaper for your setup, in your hands within three weeks.