Stories
Slash Boxes
Comments

SoylentNews is people

posted by martyb on Thursday December 02, @11:11PM   Printer-friendly [Skip to comment(s)]
from the a-little-late-for-the-JWST dept.

Colour-changing magnifying glass gives clear view of infrared light:

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.

Journal Reference:
Angelos Xomalis, Xuezhi Zheng, Rohit Chikkaraddy, et al. Detecting mid-infrared light by molecular frequency upconversion in dual-wavelength nanoantennas, Science 2021; 374 (6572): 1268 (DOI: 10.1126/science.abk2593)


Original Submission

This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
(1)
  • (Score: 2, Informative) by coolgopher on Thursday December 02, @11:17PM (1 child)

    by coolgopher (1157) Subscriber Badge on Thursday December 02, @11:17PM (#1201678)

    visAngelos Xomalis, Xuezhi Zheng, Rohit Chikkaraddy, ible light, which is easily detected.

    • (Score: 2) by Kymation on Thursday December 02, @11:36PM

      by Kymation (1047) Subscriber Badge on Thursday December 02, @11:36PM (#1201682)

      his 2021; 374 (6572): 1268 simulations of light in these building blocks.

  • (Score: 2) by Rosco P. Coltrane on Friday December 03, @12:21AM (5 children)

    by Rosco P. Coltrane (4757) on Friday December 03, @12:21AM (#1201688)

    If you have to chill current, direct infrared light sensors so they don't see their own infrared light, would you not have to chill the magic IR-to-visible light converter so it doesn't convert its own IR radiations too? It's the same problem isn't it?

    • (Score: 1) by dioxide on Friday December 03, @01:16AM

      by dioxide (7248) on Friday December 03, @01:16AM (#1201703)

      No, this adds energy to photons passing through, doesn't emit its own. Anything the sensor added would continue on in the other direction.

    • (Score: 2) by mhajicek on Friday December 03, @06:54AM

      by mhajicek (51) on Friday December 03, @06:54AM (#1201759)

      I have an infrared camera on my phone. Works fine.

      --
      The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
    • (Score: 3, Insightful) by FatPhil on Friday December 03, @08:15AM

      Inside the "lens" (I believe it's no such thing, but can't access the article) the heat is in the form of phonons. Externally arriving IR is radiation.
      However, the summary is confusing: "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". Visible light already was visible, upshifting visible light towards the blue end of the spectrum is not making IR visible. And given that A+B = B+A, one might say that the only thing that's been made visible is the phonons in the material, once stimulated by the visible light. So your point is a valid request for clarification.
      --
      I know I'm God, because every time I pray to him, I find I'm talking to myself.
    • (Score: 1, Informative) by Anonymous Coward on Friday December 03, @12:08PM (1 child)

      by Anonymous Coward on Friday December 03, @12:08PM (#1201797)

      When people hear "infrared", they always assume it is thermal infrared, also known as "longwave" infrared. This is MWIR, or mid-wave infrared, which like short-wave infrared (SWIR), does not have a strong thermal component. So there are two different issues here. The relatively inexpensive IR sensors for cell phones use microbolometers for pixels and are thermal IR sensors. The result of the effect that you are talking about is that there is an overall DC-level to the signal, which is why the output of those sensors look so noisy, but signals that are above that background level you can see. Those images would look a lot better if you could cool down the optics. MWIR sensors are less affected by thermal effects, or at least the temperatures that the optics would normally run at do not produce as many photons in the MWIR range as in the LWIR to have the effect you mention, so you don't need to really cool the optics, but the tradeoff is that MWIR sensors are not inexpensive (there isn't yet an inexpensive material to make them for your cell phones at reasonable prices).

      • (Score: 1, Interesting) by Anonymous Coward on Friday December 03, @01:06PM

        by Anonymous Coward on Friday December 03, @01:06PM (#1201799)

        The comments above stand, but as someone else pointed out, the article title says MWIR, but the abstract says ten microns, which is smack in the middle of the LWIR band. I tried to look at the actual paper itself to see if it really was talking about MWIR, but I don't have access to the paper. I find it hard to believe that such a mistake in terms would make it through the Science review process, but there it is-I don't have access to see otherwise.

  • (Score: 4, Informative) by ChrisMaple on Friday December 03, @01:06AM (2 children)

    by ChrisMaple (6964) on Friday December 03, @01:06AM (#1201700)

    We converted approximately 10-micrometer-wavelength incoming light to visible light by surface-enhanced Raman scattering (SERS) in doubly resonant antennas that enhanced upconversion by more than 10^10. We showed 140% amplification of the SERS anti-Stokes emission when an MIR pump was tuned to a molecular vibrational frequency, obtaining lowest detectable powers of 1 to 10 microwatts per square micrometer at room temperature.

    In my understanding, 10 micron is far infrared, not middle.

    This sounds like a very nice piece of science with practical applications.

    • (Score: 2) by FatPhil on Friday December 03, @08:16AM (1 child)

      Yup, the military should be all over this. Now the US will be able to kill dark people from even further distances!
      --
      I know I'm God, because every time I pray to him, I find I'm talking to myself.
      • (Score: 0) by Anonymous Coward on Monday December 06, @08:49PM

        by Anonymous Coward on Monday December 06, @08:49PM (#1202579)

        So will the sensor companies that are trying to get buy-in from self-driving car companies--a potentially huge market, IF you can break in. But the car companies are tough customers with high reliability specs in addition to low prices.

(1)