Detection of electron spin resonance down to 10 K using localized spoof surface plasmon

In this study, novel use of the electromagnetic field profile of a localized spoof surface plasmonic mode to detect electron spin resonance is being reported. The mode is supported on a resonator with a complementary metallic spiral structure, etched on the ground plane of a microstrip line having a characteristic impedance of 50 Ω. The change in characteristics of the mode of interest with lowering of temperature has been observed and analyzed. Electron spin resonance spectra of three paramagnetic samples - 2,2-Diphenyl-1-picrylhydrazyl, Galvinoxyl, and 2,2,6,6-Tetramethylpiperidine-1-oxyl are recorded using this resonator at room temperature. ESR spectra of 2,2-Diphenyl-1-picrylhydrazyl are also captured down to 10 K. Potential application of the mode in the detection of microwave induced Rashba field-driven electron spin resonance has been discussed.