Xi Qin

High-Time-Resolution Nuclear Magnetic Resonance With Nitrogen-Vacancy Centers

We present a field-programmable gate array (FPGA)-based solution for high-time-resolution nanoscale nuclear magnetic resonance, with nitrogen-vacancy centers as a probe. The Xilinx FPGA is used to implement a high-performance pulse generator, which contributes to high-precision measurement for the nuclear magnetic resonance (NMR) signal. The pulse generator outputs continuous pulses with a time resolution of 50 ps and a dynamic range of 5 ns to 2.68 s. The central control and the readout logics for the NMR experiment are fully implemented in the FPGA. We observed nanoscale NMR signals of hydrogen atoms by measuring the period of the Larmor precession with a 50 ps time resolution. Furthermore, we demonstrate the ability to distinguish signals of adjacent frequencies, which is a great advantage in high-resolution analysis for the nanoscale NMR.

Searching for an exotic spin-dependent interaction with a single electron-spin quantum sensor

Xing Rong, 2, 3, ∗ Mengqi Wang, 2, ∗ Jianpei Geng, 2, ∗ Xi Qin, 2, 3 Maosen Guo, Man Jiao, Yijin Xie, Pengfei Wang, 2, 3 Pu Huang, 2, 3 Fazhan Shi, 2, 3 Yi-Fu Cai, 5 Chongwen Zou, and Jiangfeng Du 2, 3, † CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China (USTC), Hefei 230026, China Hefei National Laboratory for Physical Sciences at the Microscale, USTC Synergetic Innovation Center of Quantum Information and Quantum Physics, USTC CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, USTC School of Astronomy and Space Science, USTC National Synchrotron Radiation Laboratory, USTC

An integrated device with high performance multi-function generators and time-to-digital convertors.

A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy (N-V) center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate-Array (FPGA). The digital compartment is designed to manage the multi-function digital waveform generation and the time-to-digital convertors. The device provides two arbitrary-waveform-generator channels which operate at a 1 Gsps sampling rate with a maximum bandwidth of 500 MHz. There are twelve pulse channels integrated in the device with a 50 ps time resolution in both duration and delay. The pulse channels operate with the 3.3 V transistor-transistor logic. The FPGA-based time-to-digital convertor provides a 23-ps time measurement precision. A data accumulation module, which can record the input count rate and the distributions of the time measurement, is also available. A digital-to-analog convertor board is implemented as the analog compartment, which converts the digital waveforms to analog signals with 500 MHz lowpass filters. All the input and output channels of the device are equipped with 50 Ω SubMiniature version A termination. The hardware design is modularized thus it can be easily upgraded with compatible components. The device is suitable to be applied in the quantum technologies based on the N-V centers, as well as in other quantum solid state systems, such as quantum dots, phosphorus doped in silicon, and defect spins in silicon carbide.

Ultra-broadband coplanar waveguide for optically detected magnetic resonance of nitrogen-vacancy centers in diamond

We report on coplanar waveguides (CPWs) designed for optically detected magnetic resonance of nitrogen-vacancy (NV) centers in diamonds. A broad band up to 15.8 GHz has been realized, which ensures that the electron spins can be manipulated under external magnetic fields up to 5000 G. The conversion factor of CPW has been measured by Rabi nutation experiments, which ranges from 6.64 G W-1/2 to 10.60 G W-1/2 in the frequency band from 0.76 GHz to 17.3 GHz. Broadband CPWs also provide high quality control pulses due to the minimization of the distortion. These characteristics will find potential applications in NV-based quantum information processing and single spin magnetometry.

A pico-second resolution arbitrary timing generator based on time folding and time interpolating

We report a pico-second resolution arbitrary timing generator which is implemented with a field-programmable-gate-array. The arbitrary timing/pattern generator is based on a time folding method which is combined with a delay chain for fine time interpolating. The time folding method can not only break the limitation of sequence time resolution contributed by the minimum chain cell delay but also improve the chain linearity. The arbitrary timing generator which is based on the time folding technique is integrated in a printed-circuit board, and a 5 ps time resolution with enhanced output linearity is obtained. The dynamic range of output pulses from the arbitrary timing generator is from 5 ns to 10 s. In this paper, we describe the principle, the circuit design, and the characterizations of the arbitrary timing generator. We also discuss the improvement of performance in timing generation using the time folding method. The high-performance arbitrary timing generator has a bright future to be used in the applications that require high-resolution timing sequence generation.