Blazed Gratings

NIL Technology makes high-quality, custom-made blazed gratings with very low roughness, surface roughness and small anti-blaze. The blazed gratings’ pitch can be down to 150 nm and the blaze angle end grating depth can be tuned to meet the required specifications.

We excel at high precision mastering and we know what it takes to realize high efficiency blazed gratings. Contact us to know more about what we can do in terms of gratings. 

We are specialized in blazed gratings

NILT is specialized in high-precision nanoscale features and complex optical structures. We have many years experience in making gratings and we have ongoing, close relationships with major high-tech companies that use gratings for research & development, innovative new products and mass production. 

High precision diffraction line grating
Tilted view of a replication from a NILT blazed grating master

Top view

Tilted view

Top- and tilted view of a replication from a NILT blazed grating master. High level of uniformity and accuracy even at the edge of the pattern. The surface roughness is caused by the gold layer needed for SEM imaging.

Our competencies with blazed gratings include:

  • All blazed parameters can be varied according to customer specifications
  • Anti-blaze can be 90° and both above and below 90°
  • Optical surface quality
  • Orientation of gratings is not linked to crystal direction. It is possible to freely mix different orientations
  • Extreme accuracy
  • Excellent uniformity

You are more than welcome to contact us if you would like to know more about blazed gratings and how we can help you. We can be your partner through the whole journey, from idea to design and production of the optical component. Read more about our services right here.

How are blazed gratings used?

Blazed gratings are usually applied within an AR/VR/MR field as incoupling gratings for wave guide displays.

The blaze angle controls which angle the light couples, while the anti-blaze controls the efficiency of the diffraction in that direction. Theoretically, if one achieves a perfect smooth blaze with no anti-blaze, 100% of the incoming light will be diffracted in the desired direction. This of course means that accuracy, uniformity and low surface roughness are of highest importance to realize such gratings – all of which are core competences at NILT.

Blazed gratings, a master with small anti-blaze for high efficiency diffraction

A blazed grating master with small anti-blaze for high efficiency diffraction

Blazed gratings are also called echelette grating (from French échelle = ladder) or saw-tooth gratings. It a special type of reflective or transmission diffraction grating that is optimized to achieve maximum efficiency in one given diffraction order.

For this purpose, maximum optical power is concentrated in the desired diffraction order, while the residual power in the other orders (particularly the zeroth) is minimized. This condition can only be achieved for a single wavelength for each grating. The direction in which maximum efficiency is achieved is called the blaze angle.

The challenge with this type of grating is that a high anti-blaze angle will reduce the efficiency of the desired diffraction order significantly.

Given our expertise within mastering and gratings, NIL Technology are able not only to minimize, but actually tune this anti-blaze angle, and thereby achieve the high efficiency diffraction that is desired.

You can read more about gratings here

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