Development of a dynamic nuclear polarization system based on the optical pumping method

We have developed a dynamic nuclear polarization system based on the optical pumping NMR method. It consists of an NMR spectrometer, laser and optical system, optical-pumping double-resonance probe, cryostat and superconducting magnet. The double-resonance probe newly developed for this system is of a top-loading type, characterized by a single-coil double-tuning tank circuit with traps. The system allows simultaneous control of two radio-frequency fields and a light beam irradiated to samples, enabling us to perform cross-polarization experiments under the optical pumping condition. As a test of the system, a cross-polarization experiment has been performed with indium phosphide doped with iron.