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| A schematic illustration of a fluorescent protein polariton laser in action. Particles made from a mixture of light and electronic energy are created in a film of green fluorescent protein produced by live cells. The particles can …more |
A
combined team of researchers from Scotland and Germany has developed a way to
create a polariton laser by using jellyfish proteins cultivated in E. coli cells. In their paper published in the
journal Science Advances, the team
describes their technique and possible uses for the result.
As most people know,
at a basic level, conventional lasers work by bouncing light around inside of a
cavity and then emitting identical photons as a beam. There is another type of
laser that is less well known, the polariton laser—it works by tossing photons
back and forth between excited molecules. But the reason it has not made its
way into commercial use is because it must be cooled to an extremely low
temperature to work properly. In this new approach, the researchers report the
development of such a laser that works at room temperatures.
To make the new
laser, the researchers grew enhanced green fluorescent protein from jellyfish
in E. coli cells because prior research
suggested they were capable of producing polaritons (quasiparticles that are
able to carry excitations with them). The protein was fashioned into a very
thin (500 nanometer) film that was set between two mirrors. To create a laser
beam, all the researchers had to do was shine a blue light into the device,
which excited the proteins to the point of producing polaritons—soon
thereafter, they spontaneously synchronized, producing a laser beam that was emitted out of
the device.
The researchers note
that others have tried to create such lasers with limited success due to the
excited particles colliding with one another—severe cooling was the only way to
tame them. But the jellyfish proteins came with a built-in solution—each was
barrel-shaped with the fluorescent molecules shielded inside, protecting the
emitted particles from interfering with one another.
The team suggests
that because the laser operates at room temperature, one of its ideal
applications might be as a laser tag
for cancer—one that is able to note the differences in wavelengths of light
bounced from cells allowing for easily identifying those that are cancerous.
They plan to search for other biological materials that might serve a similar
purpose but that do so by emitting colors other than green.
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