Dataset for "Order-of-Magnitude SNR Improvement for High-Field EPR Spectrometers via 3D-Printed Quasioptical Sample Holders"

In this paper, we present a rapidly-prototyped, cost-efficient, 3D-printed quasioptical sample holder for improving the signal-to-noise ratio (SNR) in modern, resonator-free, high-field electron paramagnetic resonance (EPR) spectrometers. Such spectrometers typically operate in induction mode: the detected EPR (``cross-polar") signal is polarized orthogonal to the incident (``co-polar") radiation. The sample holder improves SNR in three modes: continuous wave, pulsed, and rapid-scan. An adjustable sample positioner allows for optimizing sample position to maximize the 240\,GHz magnetic field $B_1$, and a rooftop mirror allows for small rotations of the cross-polar signal to maximize the signal and minimize the co-polar background.  When optimized, the co-polar isolation (the ratio of incident to detected co-polar signal) was  $\sim 50$\,dB, an improvement of $>20$\,dB. This large isolation is especially beneficial for maximizing the SNR of rapid-scan EPR, but also improves the SNR in pulsed and cwEPR experiments. Through minimal modification, the sample holder may be incorporated into a variety of homebuilt, induction-mode hfEPR spectrometers in order to significantly improve the SNR (approx. 6$\times$), and thereby reduce the acquisition time (by more than a factor of 30).