Color-changing magnifying glass gives clear view of infrared light


Date:
December 2, 2021
Source:
University of Cambridge
Summary:
By trapping light into tiny crevices of gold, researchers have
coaxed molecules to convert invisible infrared into visible light,
creating new low-cost detectors for sensing.



FULL STORY ========================================================================== Detecting light beyond the visible red range of our eyes is hard to do,
because infrared light carries so little energy compared to ambient heat
at room temperature. This obscures infrared light unless specialised
detectors are chilled to very low temperatures, which is both expensive
and energy-intensive.


==========================================================================
Now researchers led by the University of Cambridge have demonstrated a
new concept in detecting infrared light, showing how to convert it into
visible light, which is easily detected.

In collaboration with colleagues from the UK, Spain and Belgium,
the team used a single layer of molecules to absorb the mid-infrared
light inside their vibrating chemical bonds. These shaking molecules can
donate their energy to visible light that they encounter, 'upconverting'
it to emissions closer to the blue end of the spectrum, which can then
be detected by modern visible-light cameras.

The results, reported in the journal Science, open up new low-cost ways
to sense contaminants, track cancers, check gas mixtures, and remotely
sense the outer universe.

The challenge faced by the researchers was to make sure the quaking
molecules met the visible light quickly enough. "This meant we had to
trap light really tightly around the molecules, by squeezing it into
crevices surrounded by gold," said first author Angelos Xomalis from Cambridge's Cavendish Laboratory.

The researchers devised a way to sandwich single molecular layers between
a mirror and tiny chunks of gold, only possible with 'meta-materials'
that can twist and squeeze light into volumes a billion times smaller
than a human hair.

"Trapping these different colours of light at the same time was hard,
but we wanted to find a way that wouldn't be expensive and could easily
produce practical devices," said co-author Dr Rohit Chikkaraddy from
the Cavendish Laboratory, who devised the experiments based on his
simulations of light in these building blocks.

"It's like listening to slow-rippling earthquake waves by colliding
them with a violin string to get a high whistle that's easy to hear,
and without breaking the violin," said Professor Jeremy Baumberg of
the NanoPhotonics Centre at Cambridge's Cavendish Laboratory, who led
the research.

The researchers emphasise that while it is early days, there are many
ways to optimise the performance of these inexpensive molecular detectors, which then can access rich information in this window of the spectrum.

From astronomical observations of galactic structures to sensing human
hormones or early signs of invasive cancers, many technologies can
benefit from this new detector advance.

The research was conducted by a team from the University of Cambridge,
KU Leuven, University College London (UCL), the Faraday Institution,
and Universitat Polite`cnica de Vale`ncia.

The research is funded as part of a UK Engineering and Physical Sciences Research Council (EPSRC) investment in the Cambridge NanoPhotonics Centre,
as well as the European Research Council (ERC), Trinity College Cambridge
and KU Leuven.

========================================================================== Story Source: Materials provided by University_of_Cambridge. The original
text of this story is licensed under a Creative_Commons_License. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Angelos Xomalis, Xuezhi Zheng, Rohit Chikkaraddy, Zsuzsanna
Koczor-Benda,
Ermanno Miele, Edina Rosta, Guy A. E. Vandenbosch, Alejandro
Marti'nez, Jeremy J. Baumberg. Detecting mid-infrared light
by molecular frequency upconversion in dual-wavelength
nanoantennas. Science, 2021; 374 (6572): 1268 DOI:
10.1126/science.abk2593 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211202141433.htm

--- up 3 weeks, 2 hours, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)