Institution: | 1. Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
Contribution: Formal analysis (equal), Investigation (lead), Validation (lead), Writing - original draft (equal);2. Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
Contribution: Formal analysis (supporting), Software (equal), Visualization (supporting), Writing - review & editing (supporting);3. Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany;4. Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
Contribution: Funding acquisition (equal), Writing - review & editing (equal) |
Abstract: | A RASER (Radio Amplification by Stimulated Emission of Radiation) facilitates the study of nonlinear phenomena, as well as the determination of NMR parameters with high precision. To achieve maximum sensitivity in the desired operating mode, it is crucial to control the RASER over long periods of time. So far, this was only possible at ultra-low magnetic fields. Here, we introduce a way to control the operating regime of a RASER at a magnetic field of 1.45 T. We employ a continuous-flow RASER, pumped by PHIP (ParaHydrogen Induced Polarization). The hydrogenation of vinyl acetate (VA) with parahydrogen provides the required negative polarization on the methyl group of the product ethyl acetate (EA). The protons within the methyl group, separated by a 7 Hz J-coupling, are RASER active. This system demonstrates five RASER phenomena: inequivalent and equivalent amplitudes in the “normal NMR mode”, period doublings, frequency combs, and chaos. The experiments match with simulations based on a theoretical model of two nonlinear-coupled RASER modes. We predict the RASER regime at set conditions and visualize the prediction in a bifurcation diagram. |