A University of California Berkeley research team has found that twisting two graphene sheets stacked together gives the material nonlinear optical capabilities, which could have implications on everything from spectroscopy and material analysis to computers and communication tech.
Scientists studying optics separate materials as either linear or nonlinear for the purposes of their research. Shining a light at most materials, including a sheet of graphene, the resulting photons will scatter or absorb, but will remain the same color.
Nonlinear materials exposed to the same light source will have photons combine to create ultraviolet photons. It’s a naturally occurring phenomenon that can’t be altered or changed. The researchers’ study aims to use the twisted graphene sheets to dial in how the photons are combined.
“Just by introducing this twisting mechanism, electrons in the graphene layers have very different behaviors,” says Jie Yao, associate professor of materials science and engineering and the paper’s senior author. “The results are better than we thought. The nonlinear capability generated by twisting graphene layers is surprisingly strong.”
We’re only now just starting to learn of the incredible new properties of twisted graphene, and the Berkeley researchers’ study is only the latest.