How a New Ultra-Black Coating Could Vastly Improve Future Space Telescopes

It turns out that one of the keys to better images from space is making things really, really black.

Scientists developed a new kind of ultra-black coating that could make future telescopes and optical devices much more effective. In this article, we explain why.

(Image Credit: NASA, ESA, CSA, STScI/Dima Zel via Shutterstock - HDR tune by Universal-Sci)

The team developed their special coating for use on materials like magnesium alloys, which are common in aerospace and optics. 

By applying this ultra-black coating, these materials can absorb an impressive 99.3% of light. This is crucial for astronomy and other fields that rely on precision optics, as even a little bit of stray light can blur images and reduce the quality of the data collected.

The Science of Ultra-Black

The researchers' breakthrough comes from a technique known as atomic layer deposition (ALD). This technique allows for the precise placement of thin films on an object, layer by layer. It uses a gas-phase chemical process to deposit layers of materials in a sequential, self-limiting way, enabling scientists to achieve precise thickness and composition control at the atomic level.

What makes ALD particularly unique is its ability to coat very complex shapes evenly, ensuring that every nook and cranny is covered. This is very useful for complex optical devices, which often have intricate designs and shapes.

To achieve their ultra-black surface, the team used layers of aluminium-doped titanium carbide and silicon nitride. These materials work together to trap light, preventing it from reflecting off the surface. This approach has shown to be effective across a broad range of light wavelengths, from the violet light at 400 nanometers to near-infrared light at 1,000 nanometers.

The ultra-black coating is designed to adhere to curved surfaces and magnesium alloys, effectively capturing almost all light. - (Image Credit: Jin et al.)

Why Ultra-Black Coatings Can Vastly Improve Space Telescopes

But why is this so important? In the cold, vast expanse of space or in extreme conditions on Earth, current coatings just don't cut it. They either don't absorb enough light or aren't durable enough to withstand harsh environments. 

The new ultra-black coating not only excels in absorbing light but also stands up to friction, heat, moisture, and temperature changes.

This advancement is more than just a step forward for the sake of science. It has practical applications that could significantly improve the performance of space telescopes and other precision optical instruments. By cutting down on unwanted light, these devices can produce clearer, more accurate images.

Future improvements

The team behind this innovation is now working to expand the coating's light absorption capabilities even further. By extending its effectiveness to include ultraviolet and infrared light, they hope to unlock even more potential for the next generation of telescopes and optical devices. 

With this ultra-black coating, the future of exploring the cosmos looks brighter than ever—or, perhaps more fittingly, darker than ever.

If you are interested in more details about the underlying study, be sure to check out the paper published in the peer-reviewed Journal of Vacuum Science and Technology listed below.

Sources and further reading:

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