Near-field light-matter coupling of graphene antidot

In the quantum Hall localized regime, monolayer graphene patterned with a circular antidot (radius r~200 nm) supports magneto‑bound "Rydberg‑like" states under high magnetic field. We present a near‑field THz platform that addresses dipole‑allowed transitions between these quantized edge states with an on‑chip antenna. The antenna is negatively patterned in a gold film; the graphene resides in the complementary (negative) shape so that the THz hot spot overlies the antidot perimeter, providing deep‑subwavelength field confinement and enhancement. Using cryogenic THz near‑field microscopy (0.1–1 THz) under B~7 T, we map the tip induced single electron charging of these edge state while tuning level spacings with gate voltage and magnetic field. By varying antidot radius and arranging antidots into arrays, we engineer the spectrum and coupling strength. This platform provides a controlled setting to probe and tailor transport quantization (magnetic edge states) and optical quantization (THz transitions) in one device.