4-Terminal reflection and transmission in an Aharonov–Bohm ring

Measurements of electron transmission and reflection from a 4-terminal Aharonov–Bohm ring fabricated from a 2-dimensional electron gas have been made. A voltage applied to a side-gate shifts the phase of the transmission oscillations (period h/e), while the phase of the reflection oscillations (period h/2e) is essentially independent of the gate voltage. This device is the electron analog of an optical fiber loop mirror.