Time-optimized pulsed dynamic nuclear polarization.

Area of Science:

• Magnetic Resonance
• Physical Chemistry
• Quantum Optics

Background:

• Pulsed dynamic nuclear polarization (DNP) techniques enable efficient electron-nuclear polarization transfer.
• Conventional DNP methods often necessitate high-power microwave irradiation due to large Rabi frequency requirements.
• Achieving high polarization enhancement typically demands significant energy input.

Purpose of the Study:

• To introduce a novel low-power DNP sequence for static samples.
• To investigate a robust DNP condition for optimized polarization transfer.
• To reduce the microwave power required for DNP experiments.

Main Methods:

• Development of a new low-power DNP sequence (TOP-DNP) using a train of microwave pulses.
• Investigation of a specific DNP condition with a period approximately 1.25 times the Larmor period.
• Experimental validation and computational simulations at various magnetic fields.

Main Results:

• The TOP-DNP sequence achieved an enhancement factor of ~200 at 0.35 T.
• This enhancement was superior to the ~172 achieved with the NOVEL sequence.
• TOP-DNP utilized only ~7% of the microwave power required by NOVEL.
• Experimental and simulation data indicated a field-independent enhancement factor.

Conclusions:

• The proposed TOP-DNP sequence offers a highly efficient and low-power alternative for pulsed DNP.
• The method provides significant microwave power savings compared to existing techniques like NOVEL.
• The field-independent enhancement factor suggests broad applicability across different magnetic field strengths.