Detecting Axial Ratio of Microwave Field with High Resolution Using NV Centers in Diamond
Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
University of Chinese Academy of Sciences, Beijing 100049, China
CAS Key Lab of Quantum Information, University of Science and Technology of China, Hefei 230026, China
Author to whom correspondence should be addressed.
Sensors 2019, 19(10), 2347; https://doi.org/10.3390/s19102347
Received: 7 April 2019 / Revised: 14 May 2019 / Accepted: 14 May 2019 / Published: 21 May 2019
(This article belongs to the Special Issue Microwave Sensing and Imaging)
Polarization property characterization of the microwave (MW) field with high speed and resolution is vitally beneficial as the circularly-polarized MW field plays an important role in the development of quantum technologies and satellite communication technologies. In this work, we propose a scheme to detect the axial ratio of the MW field with optical diffraction limit resolution with a nitrogen vacancy (NV) center in diamond. Firstly, the idea of polarization selective detection of the MW magnetic field is carried out using a single NV center implanted in a type-IIa CVD diamond with a confocal microscope system achieving a sensitivity of 1.7
T/ . Then, high speed wide-field characterization of the MW magnetic field at the submillimeter scale is realized by combining wide-field microscopy and ensemble NV centers inherent in a general CVD diamond. The precision axial ratio can be detected by measuring the magnitudes of two counter-rotating circularly-polarized MW magnetic fields. The wide-field detection of the axial ratio and strength parameters of microwave fields enables high speed testing of small-scale microwave devices.