Available Technology

Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

Superconducting nuclear magnetic resonance (NMR) spectroscopy instruments are expensive and require cryogenic cooling. Due to market demand and technological advances, the presence of benchtop NMR that do not require cryo-cooling has been increasing. Benchtop NMR are highly advantageous for academic researchers as well as chemists working in industrial laboratories. Compact and portable Magnetic Resonant Imaging (MRI) also called Battlefield MRI have been recently demonstrated and hold the promise of making life-saving information available to doctors on the battlefield or in remote areas quickly. In both cases, more compact, and less expensive NMR and MRI that do not require cryo-cooling will make these instruments increasingly available.

Low-field MRI is a growing area of interest which places more challenges on magnetometers – specifically they must operate with high sensitivity at very low frequencies associated with low magnetic fields. This invention uses very small alkali vapor cells with a sensitivity sufficient for detecting very small DC magnetic fields produced by a small sample of fluid without cryo-cooling. The fabrication process allows for integration of the alkali vapor cell (cesium, rubidium, and potassium) adjacent to a microfluidic channel within an integral microfluidic device. The fabrication process, based on lithographically-defined patterning, is highly scalable. End-use applications include benchtop NMR, microfluidics, MRI, and reservoir analysis.

Patent Abstract: 

This technology is a device that integrates a microfluidic channel and an alkali vapor cell on a microchip-like platform. In conjunction with a near resonant laser beam, the alkali vapor cell forms the basis for an atomic magnetometer, competing with (or even exceeding) the sensitivity of magnetometers based on superconductiong quantum intereference devices (SQUIDs). A variety of applications for such a device exist, most notably the detection of magnetic flux from a polarized sample of nuclei for the measurement of nuclear magnetic resonance (NMR) and magnetic resonance imaging. In an optimized system, the detection limit of this device is superior to that demonstrated by conventional inductive detection in a 300 MHz magnet. The device can be manufactured with conventional microfabrication techniques for ease of mass production. It can be widely applied in industry whenever trace amounts of chemical are being analyzed. For example, the pharmaceutical industry could use large arrays of these devices to perform parallel assays of a set of new trial drugs.


The device provides a means of NMR detection in magnetic fields near zero. The advantages of working at small magnetic fields include that no cryogenics are required and that noise associated with currents used to null the field are minimized.


Micah Ledbetter, Igor Savukov, Dmitry Budker, Vishal Shah, Svenja Knappe, John Kitching, David Michalak, Shoujun Xu, and Alexander Pines

Patent Number: 
Technology Type(s): 
Health Care, Homeland Security, Electromagnetics, Precision Measurement, Advanced Manufacturing Processes, Materials for Electronics
Internal Laboratory Ref #: 
Patent Issue Date: 
August 9, 2011
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