Bubbles make me think of this one summer day where I made a throng of rainbow-skinned mammoths, with two chopsticks with yarn strung between them and a homemade mix of dish soap and light corn syrup. But after talking to Tony Jun Huang at Penn State, I’ll now think of nanoscale light beams.
The term he and his research team use in their research paper, published last Friday in Nature Communications, is “reconfigurable plasmofluidic lens.” I’ll still say “bubbles.”
Huang dabbles in fluidics, optics, and nanotechnology for a living. For this particular research, he and his team mixed optics with plasma physics in order to achieve things on the nanoscale.
Light waves are large compared to the tiny electrical circuits that compose our sleek computers and cell phones now, but they carry so much more information more quickly than traditional electronics. They just physically can’t fit through our tiny circuitry — haven’t you asked yet when the hell light-speed Internet will happen?
But scientists can modulate light waves onto the nanoscale by essentially copying their form with surface plasmon polaritons (SPP), which are created when a photon melds with the short electromagnetic waves that only exist along the intersection of a metal surface and a polarized insulator.
SPPs are cool because they have the carrying capacity and speed of light, but once they’re created, they like to follow a straight and narrow path and never deviate.
In our giant human world, redirecting light is a matter of glass lenses or shiny mirror-like materials, which we can shape to whatever specifications our given purpose calls for – like shifting the focal point of a camera. In the tiny nanoscale world, constructing such purposeful tools is laughable, and making them adjustable to your every whim is just as hilarious. You would also have to attain a level of craftsmanship that achieves perfection beyond what the eye can see – after all, these creations are as tiny as (and tinier than) the thickness of a sheet of paper.
So you can see where Huang’s bubbles come into play.
Because they are fluid and a different medium from air, they cause light to refract, an effect you’ve seen when someone is standing half-in and half-out of water. Adjusting the bubble’s size and shape changes the refraction angle.
Nanoscale bubbles are easy to make. Here’s the recipe.
- fluid of choice (different fluids have different refraction rates)
- surface of choice (Huang used gold)
- low-energy diode laser
- a scientist (so that you can understand the implications of your actions)
- Put fluid on surface.
- Direct laser beam at liquid.
- If you like your first bubble, keep the laser’s position and intensity constant. If not, play around until you get the effect you want.
- Shoot your SPP beam at it. Note the angle of refraction. Delight or despair, as you will. Consult your scientist.
- The bubble won’t last outside the laser beam, so if you’re done for the day, simply turn the laser off.
Obviously, redirecting light all willy-nilly is just part of a larger (if still microscopic) system. Huang’s specialty is lab-on-a-chip devices, microchip-sized wafers crammed with tiny tubes and electronics that can perform several diagnostic functions like blood tests. Here, being able to encode unfathomable amounts of information that moves at fast-as-light-because-it’s-basically-light speeds — or even just signaling a function to begin or finish — opens up more possibilities.