It works by inscribing a 3 dimensional polymer scaffold with a laser beam and then dehydrating the gel, shrinking the object by an order of 1000. They think it will create new optical meta-materials that could revolutionize electronics by packing in such a vast amount of informational complexity in to a comparatively small amount of space.
Metamaterials are a synthetic arrangement of elemental mass that leads to a tightly ordered microscopic structure. They are basically a form of artificial crystalline matter that often exhibit very unique qualities you cannot get from the natural world.
In the case of optical metamaterials you have the ability to focus or manipulate electromagnetism (light) in some manner. This is particularly useful in the emerging field of optoelectronics whereby photons (quanta of light) are the new informational bit that travel along metamaterial waveguides much in the same way as they would a larger fibre optic cable.
The study was led by Edward Boyden of the Massachusetts Institute of Technology
In the experiment they basically seared 3 dimensional patterns of reactive chemical groups in to the hydrogel scaffold using a highly energized laser beam. After that, they inject other ingredients (for example quantum dots, a piece of DNA or even gold nanoparticles) into those reactive groups in 3D, depending on what kind of effect they’re looking to illicit.
Using an acid they dehydrate the gel which compresses the polymer scaffold INCLUDING the architecture inside, reducing the overall volume by a thousand times. What you end up with is a customized nanoscale geometry that took much less time to construct then what you would otherwise have to fidget with at a microscopic scale.
In this particularly experiment they printed out a highly conductive silver nanostructure that retained it’s complexity after shrinking.
“As mentioned, most lithography techniques in use today are limited to 2D and while direct laser writing can fabricate 3D objects, these must be connected and self-supporting and must be made out of specific polymers suitable for the laser writing process,” explain team members Daniel Oran and Sam Rodriques.
“In contrast, our technique has no limitation on the geometries it can fabricate – and the structures don’t need to be self-supporting or connected. We can also directly pattern more functionally useful materials like metals or semiconductor nanocrystals.”
“Traditional lithography also requires massive fabrication facilities and extraordinarily expensive equipment along with costly and often toxic materials, they add.
“Our process makes use of very cheap biocompatible materials and more commonly available equipment (like the two-photon microscopes we employed in this work). A simple process like ours could help democratize the field.”
“Ultimately we believe that this technique will revolutionize the way people think about 3D nanofabrication,” Boyden tells Physics World.
“Ever since the invention of photolithography, nanofabrication has been dominated by planar processes in which you pattern a surface and then deposit materials onto the surface. We have extended this concept into the third dimension: we pattern a scaffold and then deposit materials volumetrically onto the scaffold.”
“In the short run, this technology will allow us to make structures of interest for photonics research (for example, specialized lenses to study the fundamental properties of light), but in the longer term, we see it being used to create new kinds of optics, electronics and metamaterials.”