Graphene provides an ideal platform for electron optics due to its light-like dispersion. Due to Klein tunneling, highly transparent pn junctions can be created by electron static gating. Electron reflection and transmissions at the boundaries can be manipulated by gate potential, enabling the quantum interference of electron waves. In analogy with optical wave propagations, Fabry-Perot interferences and Veselago lensing of carriers in graphene can be achieved in linear pn junctions. In circular geometries, the localized Dirac fermions can induce whispering gallery modes (WGM), similar to acoustic whispering galleries. In this talk, I will discuss the whispering galleries in our circular graphene resonators created by a local STM probe[1][2], as well as how the WGM states evolve as magnetic field increases. 

[1]  Zhao et al. Science 348, 6235, 672-675 (2015).

[2]  Natterer et al. Phys. Rev. Lett. 114, 245502 (2015).

[3]  Ghahari et al. Science 356, 6340, 845-849 (2017)

Graphene provides an ideal platform for electron optics due to its light-like dispersion. Due to Klein tunneling, highly transparent pn junctions can be created by electron static gating. Electron reflection and transmissions at the boundaries can be manipulated by gate potential, enabling the quantum interference of electron waves. In analogy with optical wave propagations, Fabry-Perot interferences and Veselago lensing of carriers in graphene can be achieved in linear pn junctions. In circular geometries, the localized Dirac fermions can induce whispering gallery modes (WGM), similar to acoustic whispering galleries. In this talk, I will discuss the whispering galleries in our circular graphene resonators created by a local STM probe[1][2], as well as how the WGM states evolve as magnetic field increases. 

[1]  Zhao et al. Science 348, 6235, 672-675 (2015).

[2]  Natterer et al. Phys. Rev. Lett. 114, 245502 (2015).

[3]  Ghahari et al. Science 356, 6340, 845-849 (2017)