A Magic Angle Spinning Activated 17O DNP Raser

In the raser effect, a sample spontaneously emits continuous radiofrequency radiation, allowing exceptionally narrow NMR line widths to be recorded without applying pulses. To achieve this phenomenon, a large negative magnetization must be induced, which we show here can be achieved for the O-17 magnetization of isotopically labeled Gd-doped CeO2 using solid effect dynamic nuclear polarization (DNP), at high field and 110 K. This allows a 2 mHz line width to be measured, which is limited only by the magnetic field stability. The raser effect can be reversibly activated and deactivated by magic angle spinning (MAS), which modulates the nuclear spin coherence lifetime. The use of MAS DNP to enable the raser effect should be further applicable to other systems and nuclei.

Automated summary

The raser effect is achieved through solid effect dynamic nuclear polarization, allowing exceptionally narrow NMR line widths to be recorded, limited only by the magnetic field stability. The reversible activation and deactivation of the raser effect can be modulated by magic angle spinning, adjusting the coherence lifetime of nuclear spins.