Loop Gap Resonators for Spin Resonance Spectroscopy

Abstract

Improved loop-gap resonators applicable to Electron-Spin Resonance spectroscopy and to quantum computing employ interdigitated capacitor structures to dramatically increase the capacitance of the resonator, along with corresponding decreases in loop size to enable measurements of small-volume samples or individual quantum bits (qubits). The interdigitated-capacitor structures are designed to minimize parasitic inductance.

1 . A resonator for coupling electromagnetic radiation to a sample on the scale of a quantum object embodying a qubit, the resonator comprising:
 an electrically conductive member;   an opening through the member defining an inductive loop in the member, the sample at least partially receivable within the opening; and   an elongated gap in the member defining a continuous convoluted path having a length between a boundary of the member and the opening,   wherein the continuous convoluted path comprises a plurality of path segments and changes of direction therebetween,   wherein the electrically conductive member comprises an interdigitated capacitor, wherein the interdigitated capacitor comprises a plurality of interlaced legs, wherein electrical current flows in opposite directions along alternate legs within the plurality of interlaced legs, thereby causing the corresponding magnetic fields to cancel out to a first order.