Ultimate limits to magnetic imaging

An inverse transformation based on the Fast Fourier Transform (FFT) can be used to convert two-dimensional (2-D) images of magnetic field into corresponding images of the 2-D source currents that generated the field. We discuss the ultimate limits to the spatial resolution that can be obtained in such current density images when information about the sample is incorporated into the inversion process. We discuss the key parameters and compare our theory to experimental data obtained from a high-T/sub c/ scanning SQUID microscope.