Figure 6
(a) Diagram of setup to test sensor operating range. A gradiometer is placed in a 4-layer mu-metal shield with Helmholtz coils to provide magnetic field along cylindrical shield can axis and two saddle coils to provide field in the transverse directions. Helmholtz and saddle coils embedded in the sensor compensate for DC fields from the shield’s coils. Sensitivity as a function of (b) the transverse field offset, parallel to pump/probe laser, (c) the transverse field offset, orthogonal to laser and sensitive direction, and (d) the field offset in sensitive direction