Lab Spotlight

NIST’s “Whispering Gallery” for Graphene Electrons

NIST whispering gallery

An international research group led by NIST scientists has developed a technique for creating nanoscale whispering galleries for electrons in graphene. This technique could be used to build devices that focus and amplify electrons just as lenses focus light.

In some structures, such as the dome in St. Paul's Cathedral in London, a person standing near a curved wall can hear the faintest sound made along any other part of that wall. This phenomenon, called a whispering gallery, occurs because sound waves will travel along a curved surface much farther than they will along a flat one. Whispering galleries are found in applications ranging from sensing, spectroscopy, and communications to the generation of laser frequency combs. Scientists have also used this principle to build whispering galleries for light waves.

Voltage from a scanning tunneling microscope (STM) is used to push graphene electrons out of a nanoscale area to create the whispering gallery, which is like a circular wall of mirrors to the electron.

The team can control the size and strength, i.e., the leakiness, of the electronic whispering gallery by varying the STM tip's voltage. The probe not only creates whispering gallery modes, but can detect them as well.

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