Observation of a Dirac point in microwave experiments with a photonic crystal modeling graphene

Understand

We present measurements of transmission and reflection spectra of a microwave photonic crystal composed of 874 metallic cylinders arranged in a triangular lattice.

• The spectra show clear evidence of a Dirac point, a characteristic of a spectrum of relativistic massless fermions.
• In fact, Dirac points are a peculiar property of the electronic band structure of graphene, whose properties consequently can be described by the relativistic Dirac equation.
• In the vicinity of the Dirac point, the measured reflection spectra resemble those obtained by conductance measurements in scanning tunneling microscopy of graphene flakes.