From the The DNP-NMR Blog:
Phase cycling with a 240 GHz, free electron laser-powered electron paramagnetic resonance spectrometer
This is not an article directly related to DNP spectroscopy. However, it shows the tremendous progress made in the development of high-frequency, high-power sources that can be utilized for high-field EPR and eventually DNP experiments.
<div>Edwards, D.T., et al., Phase cycling with a 240 GHz, free electron laser-powered electron paramagnetic resonance spectrometer. Phys. Chem. Chem. Phys., 2013.
http://dx.doi.org/10.1039/C3CP44492A
<div style="text-align: justify;">Electron paramagnetic resonance (EPR) powered by a free electron laser (FEL) has been shown to dramatically expand the capabilities of EPR at frequencies above [similar]100 GHz, where other high-power sources are unavailable. High-power pulses are necessary to achieve fast (