Exploring Absolute Black

I recently found this piece of news:

Early this year a research team at Rensselaer Polytechnic Institute and Rice University managed to create a carbon nanotube array which absorbs more than 99.9% light. Following is an excerpt from the press release at http://news.rpi.edu/update.do :

“It is a fascinating technology, and this discovery will allow us to increase the absorption efficiency of light as well as the overall radiation-to-electricity efficiency of solar energy conservation,” said Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university’s Future Chips Constellation, who led the research project. “The key to this discovery was finding how to create a long, extremely porous vertically-aligned carbon nanotube array with certain surface randomness, therefore minimizing reflection and maximizing absorption simultaneously.” 

The research results were published in the journal Nano Letters.

All materials, from paper to water, air, or plastic, reflect some amount of light. Scientists have long envisioned an ideal black material that absorbs all the colors of light while reflecting no light. So far they have been unsuccessful in engineering a material with a total reflectance of zero.

The total reflectance of conventional black paint, for example, is between 5 and 10 percent. The darkest manmade material, prior to the discovery by Lin’s group, boasted a total reflectance of 0.16 percent to 0.18 percent.

Lin’s team created a coating of low-density, vertically aligned carbon nanotube arrays that are engineered to have an extremely low index of refraction and the appropriate surface randomness, further reducing its reflectivity. The end result was a material with a total reflective index of 0.045 percent — more than three times darker than the previous record, which used a film deposition of nickel-phosphorous alloy.

“The loosely-packed forest of carbon nanotubes, which is full of nanoscale gaps and holes to collect and trap light, is what gives this material its unique properties,” Lin said. “Such a nanotube array not only reflects light weakly, but also absorbs light strongly. These combined features make it an ideal candidate for one day realizing a super black object.”

At www.thinkartificial.org (a highly recommendable blog) the following was said in response to the above press release

http://www.thinkartificial.org/technology/envisioning-absolutely-dark-material/#more-644

Envisioning Complete Darkness

To my knowledge, the visual properties of absolutely dark materials would be void. No depth, no texture, no reflection. The following examples depict what this might look like — but admittedly, the full effect would be twice as potent if we had 3D models and motion.

THE HOUSE
Imagine an object with zero reflection. Your house: It is impossible to detect any corners, textures or shapes inside its outline. Depth is perceptually eradicated. All that remains is your house’s silhouette; a black monolithic structure against a clouded sky.

THE ART EXHIBIT
For a more potent example, we’re at an art exhibit and we’re looking at a picture that appears to be just a black canvas. It actually looks more like a hole in the wall as there’s no visible shade or texture. Growing bored of it, we start walking towards the next picture — but notice something curious: Now that we’re looking at the black painting from the side, we see that it actually has a sharp spear protruding from its center. A spear that earlier was only 4 centimeters from our eye, waiting to scratch our cornea.

Left: Absolutely dark painting/sculpture, seen head-on.
Right: Same painting, seen from the side.

Forget pointing a flashlight at it, eye-piercing fluorescent lighting or even Hollywood’s entire arsenal of flood-lights: this painting would still look exactly like what’s pictured above. Dark.

That’s completely dark material to our gray matter.

This achievement by the research team at Rensselaer Polytechnic Institute and Rice University has made me remember a project I submitted back at The Academy named ‘Architectural Ephemerides – Exploring Absolute Black’. It was a project with the goal of describing the impact ‘absolute black’ would have on architecture by 1) breaking down conventional 3D volumetric experience into something in between two and three dimensions and 2) by allowing an unprecedented control of light by physically manipulating (abruptly or gradually) the absorption properties of the faces of built volumes; in a sense, forcing light to spray-paint itself onto volumes.

Below is the final presentation material from autumn 1999:

 

 

I have decided to take up the project again – on a very non-committed level – to delve a little bit deeper into the concept of absolute black. I will probably have to reiterate some of the material I had gathered back then; it’s all been lost over the years. This will constitute a good handful of blogs scattered over the next months, I guess. From then on I expect I can begin the further “research” into the impact of absolute black.

In order to differentiate between the old project from The Academy in 1999 ‘Architectural Ephemerides – Exploring Absolute Black’ and this new continuation, I have decided to give the new project the name of ‘The Ephemeris Dimension – Exploring Absolute Black’, so as to also maintain some connection. The stated goal of the project (above) will remain exactly the same.

Looking up the definition of Ephemeris, or Ephemerides in plural, one will find that it means: “An astronomical almanac giving, as an aid to the astronomer and navigator, the locations of celestial bodies for each day of the year”. It’s etymological context includes the Greek word for day, daily and diary which in turn obviously also sits behind the word ephemera(l).

I imagine the exploration of black as somehow trying to ‘keep track of or map the locations of light photons for each nanosecond’ just like the astronomical almanac keeps track of celestial bodies for each day.