Time domain measurement of electron spin relaxation at high fields and dynamic nuclear polarization at sub-millimeter wavelengths

We describe a 395 GHz pulsed electron paramagnetic resonance (EPR) setup, and initial results of relaxation measurements and cw EPR at these frequencies in samples used for liquid- and solid-state nuclear magnetic resonance enhanced by dynamic nuclear polarization (DNP). Depending on the amount of spin — orbit coupling, the spin lattice relaxation becomes significantly faster at higher fields and frequencies, which has consequences for some DNP applications at high fields and frequencies. We will discuss the requirements for (sub)millimeter-wave sources and components for DNP and pulsed EPR at even higher frequencies and fields, as even higher magnetic fields will become available in the near future.