Laser-focused and not thick

I told you last time that we’re going for lasers today, and here they are. When we think lasers, we often think of cylindrical thingies with some kind of bulb at the end. Maybe even some light shooting through a crystal. Or maybe just a whole lot of pew pew pew.

632px-phasr_rifle
Public Domain (Author: U.S. Air Force, 2005)

(relax, it’s just a dazzler, we’re not preparing to fight off against a threat from the Flood)

What makes this week’s Featured Article so important is that, as Karl et al. attest, while we have stretchy electronics like solar cells and LED readouts, we don’t seem to have lasers that could come shooting out of stretchy material. Why not, indeed – the previous two pieces of tech that I mentioned were once highly rigid, and now they can flex their way onto any surface. The main difficulty might come from the nature of lasers themselves: this is coherent radiation, meaning that the light (or any kind of electromagnetic radiation like X-rays or even infrared, but let’s stick to ‘light’ or ‘radiation’ as visible light, shall we?) is in a narrow set of wavelengths, which is why laser light is often an intense color that looks ‘concentrated,’ you might think:

laser-11646_640
Public Domain (Author: WikiImages, 2012)

Another reason why laser devices are bulky apart from the laser material is because you still need a power source, obviously. To be clear, any talk of ‘laser material’ in this post from now on refers to all the other parts of a laser apart from the power source.

But if coherence comes from the laser material not changing its properties, especially shape, when how can we get lasers once the laser material starts bending? According to the authors, the know-how is there in the form of distributed feedback (DFB) lasers (short story – it looks like microscopic tile roofing and it guides the radiation into something coherent), but the material is still rather thick, thus not as flexible as they might like. In order to make these lasers into literally membranes (so now you have an idea of what kind of thickness Karl et al. is going for), the authors propose a different method of building lasers: stacking the laser materials on top of glass, then using water to float it away. That’s about the gist of it: simple, elegant, and all you need are material components with names that you can’t easily pronounce. If you’re more inclined towards materials and polymers, the Featured Article is open access if you want to know more about how they built it. For the rest of us non-materials chemists and laser construction experts – the authors have created a flexible, plastic lasagna that will emit laser light when you shoot laser radiation at it.

lasagna-283254_640
Public Domain (Author: Anna, 2010)

We need note that it’s not just letting laser light through, like shining your laser pointer through a piece of glass. In fact, that actually scatters laser light into something that isn’t considered a ‘laser beam’ anymore. The laser material must keep any radiation coherent, otherwise it’s really just a flashlight. A really cool flashlight that wouldn’t be out of place in, say, the Ultra Music Festival, but not in a laboratory setting.

laser-288611_640
Public Domain (Author: LoggaWiggler, 2014)

What kind of laboratory settings would these flexible laser materials be food for? For one, the authors suggest applying these membranes on banknotes as a security feature. The way it works is through exciting the laser material: by shooting a laser or some kind of radiation at it, the laser material would then emit its own distinct laser signal. What makes it a good security measure is that the ‘laser lasagna’ is made up of many channels (kind of like actual lasagna – what a rather apt metaphor, yeah?) that could act as a barcode to track bills. Their methods would allow for one quadrillion different combinations of barcodes that could, in my opinion, have one specific barcode for every banknote ever printed. That’s a lotta banknotes (unless we’re talking about massive inflation, but this is not an economics blog).

Another use – security tags that you could wear on your eye.

person-1205140_640
Public Domain (Author: Petra, 2015)

It should be noted that at 200 nm, these membranes are 150 times thinner than a contact lens, so it’s not that cringe-inducing (although I would much rather wear glasses because I’m afraid of poking myself in the eye). Yes, there is already such thing as a retinal scan that uses biometrics for security, but too many retinal scans or bad equipment could cause problems in the long run. Not cool for people who actually intend to stay in their place of employment, especially in these uncertain economic times-

THIS IS NOT AN ECONOMICS BLOG, STOP THAT

-anyway,  these could be used so that less-intense radiation could be used to shine into your eye. It triggers the laser, which will direct the light out of your eye and back into some detector, then you could come in, sit at your desk, and have radiation come into your eyes because you’re in front of your computer anyway. I know this has important implications for high-security clearance jobs, yet I can’t help but think of social commentary at this point: rows and rows of office workers with glowing eyes. That sounds like the cover for Laser Lasagna’s debut album…

Thoughts? Comments? Any other ideas for what you could do with these membrane laser materials? Let me know in the space below, throw a like if you liked it, and you don’t need to be a WordPress member to do it! If you’re not doing so already, please follow (if you’re into scientific research with snarky commentary from an overly-caffeinated blogger-scientist) and thanks again for stopping by.

Featured Article: Karl M, Glackin JME, Schubert M, Kronenberg NM, Turnbull GA, Samuel IDW, Gather MC. (2018) Flexible and ultra-lightweight polymer membrane lasers. Nature Communications 9:1525. DOI: 10.1038/s41467-018-03874-w.

Featured Image: Public Domain (Author: 12019 (inactive Pixabay account), 2011)

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