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Dressed Rabi Oscillation in a Crystalline Organic Radical
C Blake Wilson1,2, Devin T Edwards1,2, Jessica A Clayton1,2
1Department of Physics, University of California, Santa Barbara, Santa Barbara, California, USA.
Abstract:
Free electron laser-powered pulsed electron paramagnetic resonance experiments performed at 240 GHz/8.56 T on the crystalline organic radical 1,3-bisdiphenylene-2-phenylallyl reveal a tip-angle dependent resonant frequency. Frequency shifts as large as 11 MHz (45 ppm) are observed during a single Rabi oscillation. We attribute the frequency shifts to a "dressing" of the nutation by spin-spin interactions. A nonlinear semiclassical model which includes a temperature- and sample-geometry-dependent demagnetizing field reproduces experimental results. Because experiments are performed without a cavity, radiation damping, the most common nonlinear interaction in magnetic resonance, is negligible in our experiments.
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