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

Technology #16243

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FIG. 1. The Walsh reconstruction method for measuring time-varying field with quantum probes. a, A single NV cen- ter in diamond, optically intialized and read out by confocal microscopy, is manipulated with coherent control sequences to measure the arbitrary profile of time-varying magnetic fields radiated by a coplanar waveguide under ambient conditions. b, Coherent control sequences, acting as digital filters on the evolution of the qubit sensor, extract information about time- varying fields. c, An N-point functional approximation of the field is obtained by sampling the field with a set of N digital filters taken from the Walsh basis, which contain some known set of decoupling sequences such as the even-parity CPMG sequences and the odd-parity PDD sequences.
Categories
Inventors
Professor Paola Cappellaro
Department of Nuclear Science and Engineering, MIT
External Link (web.mit.edu)
Alexandre Cooper-Roy
Department of Nuclear Science and Engineering, MIT
Managed By
Dave Sossen
MIT Technology Licensing Officer
Patent Protection

Time-resolved magnetic sensing with electronic spins in diamond

US Patent Pending US 2014-0340085
Publications
Time-resolved magnetic sensing with electronic spins in diamond
Nature, 24 January 2014
Reconstructing the profile of time-varying magnetic fields with quantum sensors
The Physical Review, 12 September 2013

Applications

This invention can be used for the measurement of weak electric and magnetic fields at the nanometer scale in fields ranging from materials science to fundamental physics and biomedical science.

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.

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.

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.