Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A cavity is coupled with a spin ensemble, and a drive field generates an interaction between the cavity and the spin ensemble. In some cases, the interaction increases the polarization of the spin ensemble faster than the thermal (T1) relaxation process or any other thermal polarizing process affecting the spin ensemble. In some cases, polarization is increased by iteratively acting on angular momentum subspaces of the spin ensemble, and mixing the angular momentum subspaces, for example, by a dipolar interaction, a transverse (T2) relaxation process, application of a gradient field, or a combination of these and other processes.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A resonator applies drive field to a spin ensemble in a static magnetic field. The drive field couples the spin ensemble with a cavity, and the coupling increases the polarization of the spin ensemble. In some cases, the cavity is detuned from the spin- resonance frequency, and the Rabi frequency associated with the drive field can be matched to the cavity detuning.

Abstract: A method for applying a nuclear magnetic resonance (NMR) sequence is described herein. The method includes applying a series of refocusing pulses to a substance within an inhomogeneous static magnetic field. Each refocusing pulse in the series of refocusing pulses includes a central axis, a total pulse duration greater than t180, and at least five segments (e.g., 5, 7, 11, 20, and 21). The phase of each segment is substantially anti-symmetric about the central axis of the refocusing pulse. In a more particular embodiment, the phase of each segment is also symmetric about the central axis of the refocusing pulse and the five segments include a substantially constant amplitude.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A resonator applies drive field to a spin ensemble in a static magnetic field. The drive field couples the spin ensemble with a cavity, and the coupling increases the polarization of the spin ensemble. In some cases, the cavity is detuned from the spin- resonance frequency, and the Rabi frequency associated with the drive field can be matched to the cavity detuning.

Abstract: In some aspects, polarization of a spin ensemble can be increased using cavity-based techniques. A cavity is coupled with a spin ensemble, and a drive field generates an interaction between the cavity and the spin ensemble. In some cases, the interaction increases the polarization of the spin ensemble faster than the thermal (T1) relaxation process or any other thermal polarizing process affecting the spin ensemble. In some cases, polarization is increased by iteratively acting on angular momentum subspaces of the spin ensemble, and mixing the angular momentum subspaces, for example, by a dipolar interaction, a transverse (T2) relaxation process, application of a gradient field, or a combination of these and other processes.

Abstract: A method for applying a nuclear magnetic resonance (NMR) sequence is described herein. The method includes applying a series of refocusing pulses to a substance within an inhomogeneous static magnetic field. Each refocusing pulse in the series of refocusing pulses includes a central axis, a total pulse duration greater than t180, and at least five segments (e.g., 5, 7, 11, 20, and 21). The phase of each segment is substantially anti-symmetric about the central axis of the refocusing pulse. In a more particular embodiment, the phase of each segment is also symmetric about the central axis of the refocusing pulse and the five segments include a substantially constant amplitude.