Reconstruction of Arbitrary Temporal Profiles of External Field with a Quantum Probe

Technology      

The invention is a method to efficiently reconstruct arbitrary time dependence of external parameters by manipulation of the quantum probe with Walsh-function-based pulsed control. Control pulses generate digital filters that extract information about the variation of the external parameter in the time domain and allow reconstructing its waveform. The system is implemented using a diamond structure that includes nitrogen-vacancy (NV) centers for sensing magnetic and electric fields. An arbitrary waveform generator and microwave waveguides manipulate the quantum spins in the diamond structure using a plurality of coherent control sequences to measure the arbitrary profile of time-varying magnetic fields. A laser optically addresses the quantum spins in the diamond structure for initialization and readout.  

Problem Addressed

Quantum probes can measure time-varying fields with high sensitivity and spatial resolution, but existing measuring techniques are limited to the measurement of constant (DC) or oscillating (AC) parameters. Therefore, there is a need for a method of measuring time-varying fields with unknown dynamics.  

Advantages

• This approach provides accurate and efficient reconstruction in the time domain with minimal reconstruction error
• The control technique used is robust against dephasing noise, as it acts as a dynamical decoupling (DD) sequence  

Publications

"Time-Resolved Magnetic Sensing with Electronic Spins in Diamond." Nature Communications, January 24, 2014.

"Reconstructing the Profile of Time-Varying Magnetic Fields with Quantum Sensors." Physical Review A, September 12, 2013.