Their new laser, claimed to be the smallest in the world, is so small that it cannot be seen with the naked eye.
The laser was built using a 30 nm gallium nitride nanorod that is partially filled with indium gallium nitride. The nanorod is placed on a 5 nm thin silicon dioxide gap layer that is sandwiched between the nanorod and an "atomically smooth" 28 nm silver film. Chih-Kang “Ken” Shih, professor of physics at The University of Texas at Austin, said that “atomic smoothness is key to building photonic devices that don’t scatter and lose plasmons, which are waves of electrons that can be used to move large amounts of data." Shih said that he has been experimenting and improving the material for more than 15 years.
So far, the size and performance of photonic devices have been restricted by what is known as the three-dimensional optical diffraction limit, which was described by two German researchers in a paper published in Laser & Photonics Reviews earlier this year. However, their new, green light emitting laser operates "well below" the 3D diffraction limit. Shih and his team believe that their tiny laser will have a huge impact on photonic chip development and promote the development of chips that are fully photonic and integrate “on-chip” communication systems.