Nav: Home

Scientists find a way to extract color from black

March 27, 2020

Scientists have developed a way of extracting a richer palette of colours from the available spectrum by harnessing disordered patterns inspired by nature that would typically be seen as black.

Colours that we see in nature often come from nanoscale patterns that reflect light back in particular ways. A butterfly's wing, for example, might appear blue because tiny grooves in the surface of the wing cause only blue light to be reflected.

When surfaces appear black or white, however, it's often because the nanoscale structures are completely disordered, causing all the light to be either absorbed or reflected.

A team of researchers led by the University of Birmingham has now found a way to control the way light passes through these disordered surfaces to produce vivid colours.

The team, which includes colleagues in Ludwig Maximilian University of Munich, Germany, and Nanjing University in China, has compared the method to techniques that artists have exploited for centuries. Among the most famous examples of this is the fourth-century Roman Lycurgus cup, made from glass that appears green when light shines on it from the front, but red when light shines through it from behind.

In a modern advance, the research team demonstrated a way of finely controlling this effect to produce extraordinarily precise colour reproduction.

The different colours in the image are represented in different thicknesses of a transparent material - such as glass - on a lithographic plate. On top of this, the researchers deposited the disordered layer - in this case made of random clusters of gold nanoparticles. Finally, beneath this layer, the team placed a mirrored to form a transparent cavity. The cavity is able to trap particles of light, or photons, inside. The photons behave like waves inside the cavity, resonating at different frequencies beneath the lithographic surface and releasing different colours according to the length of each wave.

By using this technique, the team was able to reproduce a Chinese water colour painting with exquisite colour accuracy.

Lead researcher, Professor Shuang Zhang, explains: "The different ways in which nature can produce colour are really fascinating. If we can harness them effectively, we can open up a treasure trove of richer, more vivid colours than we have yet seen."

Co-author Dr Changxu Liu adds: "In physics, we're used to thinking that randomness in nanofabrication is bad, but here we show that randomness can lead to be superior to an ordered structure in some specific applications. Also, the light intensity within the random structures that we produced is really strong - we can use that in other areas of physics such as new kinds of sensing technologies."
-end-
Notes to editor:

The University of Birmingham is ranked amongst the world's top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 6,500 international students from over 150 countries.

Publication details: Mao et al (2020). 'Manipulating disordered plasmonic systems by external cavity with transition from broadband absorption to reconfigurable reflection'. Nature Communications, 11, 1538 (2020)

University of Birmingham

Related Photons Articles:

Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.
An advance in molecular moviemaking shows how molecules respond to two photons of light
Some of the molecules' responses were surprising and others had been seen before with other techniques, but never in such detail or so directly, without relying on advance knowledge of what they should look like.
The imitation game: Scientists describe and emulate new quantum state of entangled photons
A research team from ITMO University, MIPT and Politecnico di Torino, has predicted a novel type of topological quantum state of two photons.
What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.
Producing single photons from a stream of single electrons
Researchers at the University of Cambridge have developed a novel technique for generating single photons, by moving single electrons in a specially designed light-emitting diode (LED).
Counting photons is now routine enough to need standards
NIST has taken a step toward enabling universal standards for single-photon detectors (SPDs), which are becoming increasingly important in science and industry.
Scientists have found out why photons flying from other galaxies do not reach the Earth
In the Universe there are extragalactic objects such as blazars, which very intensively generate a powerful gamma-ray flux, part of photons from this stream reaches the Earth, as they say, directly, and part -- are converted along the way into electrons, then again converted into photons and only then get to us.
Researchers discover new way to split and sum photons with silicon
A team of researchers at The University of Texas at Austin and the University of California, Riverside have found a way to produce a long-hypothesized phenomenon -- the transfer of energy between silicon and organic, carbon-based molecules -- in a breakthrough that has implications for information storage in quantum computing, solar energy conversion and medical imaging.
Breaking the limits: Discovery of the highest-energy photons from a gamma-ray burst
Gamma-ray bursts (GRBs) are brief and extremely powerful cosmic explosions, suddenly appearing in the sky, about once per day.
Massive photons in an artificial magnetic field
An international research collaboration from Poland, the UK and Russia has created a two-dimensional system -- a thin optical cavity filled with liquid crystal -- in which they trapped photons.
More Photons News and Photons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.