A W-Band Electron Paramagnetic Resonance Probe Based on Fabry-Perot Cavity

doi:10.11938/cjmr20243111

Abstract

Abstract:

This paper presents a new W-band electron paramagnetic resonance (EPR) probe design based on Fabry-Perot cavity. In this probe, a Fabry-Perot cavity with open structure and large effective volume is used as a resonator. Corrugated waveguides are designed to achieve low-loss microwave signal transmission between the W-band microwave bridge and the Fabry-Perot cavity. The probe works in W-band, and the unloaded quality factor is 1 542. A room-temperature continuous wave EPR experiment with Mn(II) in CaO powder was conducted after assembling the probe into a W-band EPR spectrometer. The results show that the modulation field amplitude is 8.9 G (1 G=10^-⁴ T) when the modulation field frequency is set to 100 kHz, and the absolute spin sensitivity is estimated to be 6.6×10⁸spins/(G•$\sqrt{Hz}$), which verifies the feasibility of utilizing Fabry-Perot cavity as a high sensitivity W-band EPR probe.

Key words: electron paramagnetic resonance (EPR), Fabry-Perot cavity, corrugated waveguide, sensitivity

CLC Number:

O482.53

LUO Wenyou, RONG Xing. A W-Band Electron Paramagnetic Resonance Probe Based on Fabry-Perot Cavity[J]. Chinese Journal of Magnetic Resonance, 2024, 41(4): 393-404.

Figures/Tables 10

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名称	参数
样品	Mn标样品
温度	室温
微波功率	2.8 mW
时间常数	100 ms$({{f}_{\text{d}}}=0.78\text{ Hz)}$
调制场频率	100 kHz
调制场幅度	4.4 G
扫场范围	3.31~3.38 T
扫描点数	1750

序号	频率/GHz	探头种类	灵敏度/ （spins/(G•$\sqrt{Hz}$)）	极化度	室温灵敏度/ （spins/(G•$\sqrt{Hz}$)）
1^[34]	94	圆柱形谐振腔	$2.0\times 1{{0}^{7}}$@300 K	0.7515%	$2.0\times 1{{0}^{7}}$
2^[22]	95	法布里-珀罗谐振腔	$3.0\times 1{{0}^{8}}$@130 K	1.753%	$7.0\times 1{{0}^{8}}$
3^[35]	94	非谐振	$1.0\times 1{{0}^{9}}$@1.5 K	90.57%	$1.2\times 1{{0}^{11}}$
4（本工作）	94	法布里-珀罗谐振腔	$6.6\times 1{{0}^{8}}$@300 K	0.7515%	$6.6\times 1{{0}^{8}}$