Microfluidic cell and a spin resonance device for use therewith

1. A microfluidic cell comprising:

a microfluidic channel for receiving a fluid sample; and

a sensor located adjacent the microfluidic channel;

wherein the sensor comprises a diamond material comprising one or more quantum spin defects;

wherein the diamond material forms at least a portion of the wall defining the microfluidic device,

wherein the one or more quantum spin defects are positioned at a distance equal to or less than 100 nm from said portion of the wall of the microfluidic channel, and

wherein the one or more quantum spin defects have a decoherence time T 2 equal to or greater than 0.05 ms.

2. A microfluidic cell according to claim 1 , wherein at least one portion of the diamond material is formed of a single crystal diamond material having one or more of: a neutral single substitutional nitrogen concentration equal to or less than 20 ppb, 10 ppb, 5 ppb, 1 ppb or 0.5 ppb; an NV − concentration equal to or less than 0.15 ppb, 0.1 ppb, 0.05 ppb, 0.001 ppb, 0.0001 ppb or 0.00005 ppb; and a total concentration of 13 C equal to or less than 0.9%, 0.7%, 0.4% 0.1%, 0.01%, or 0.001%.

3. A microfluidic cell according to claim 2 , wherein at least one further portion of the diamond material is formed of a single crystal diamond material having one or more of: a single substitutional nitrogen concentration equal to or greater than 30 ppb, 50 ppb, 100 ppb, 200 ppb, 300 ppb, 500 ppb, 700 ppb, or 800 ppb; an NV − concentration equal to or greater than 0.3 ppb, 0.5 ppb, 1 ppb, 2 ppb, 3 ppb, 5 ppb, 7 ppb, or 8 ppb; and a natural abundance of 13 C.

4. A microfluidic cell according to claim 3 , wherein the at least one further portion has a neutral single substitutional nitrogen concentration greater that the at least one portion by a factor of at least 5, 10, 20, 50, 100, 500, 1000, or 10000.

5. A microfluidic cell according to claim 3 , wherein the at least one further portion has one or more of: a neutral single substitutional nitrogen concentration equal to or less than 5 ppm, 2 ppm, or 1 ppm; and an NV − concentration equal to or equal to or less than 50 ppb, 20 ppb, or 10 ppb.

6. A microfluidic cell according to claim 1 , wherein the one or more quantum spin defects comprise one or more NV − defects.

7. A microfluidic cell according to claim 1 , wherein an out-coupling structure is formed at a surface of the diamond material for increasing out-coupling of light.

8. A microfluidic cell according to claim 7 , wherein the out-coupling structure is formed in a surface of the diamond material whereby the out-coupling structure is integrally formed by the diamond surface of the diamond material.

9. A spin resonance device comprising:

a microfluidic cell according to claim 1 and a spin resonance device comprising a cell receiving bay for receiving the microfluidic cell, the spin resonance device further comprising:

a first variable oscillating field generator for manipulating quantum spins within a sample disposed within the microfluidic channel of the microfluidic cell when mounted in the cell receiving bay;

a second variable oscillating field generator for manipulating the one or more quantum spin defects in the sensor of the microfluidic cell when mounted in the cell receiving bay;

a light source for optically pumping the one or more quantum spin defects in the sensor of the microfluidic cell when mounted in the cell receiving bay; and

a detector for detecting emission from one or more decaying quantum spin defects in the sensor of the microfluidic cell when mounted in the cell receiving bay.

10. A spin resonance device according to claim 9 , wherein the first variable oscillating field generator and the second oscillating variable field generator are magnetic or electric field generators.

11. A spin resonance device according to claim 9 , further comprising a static field generator.

12. A spin resonance device according to claim 9 , wherein the cell receiving bay is configured to removable mount the microfluidic cell.

13. A spin resonance device according to claim 9 , further configured to separately address quantum spin defects along the microfluidic channel to monitor chemical processes as they proceed down the microfluidic channel.

14. A microfluidic cell according to claim 1 , wherein the one or more quantum spin defects are positioned at a distance from the microfluidic channel equal to or less than: 80 nm; 50 nm; 30 nm; 20 nm; or 10 nm.

15. A microfluidic cell according to claim 1 , wherein said portion of the wall is terminated with a spin-zero species.

16. A microfluidic cell according to claim 1 , wherein said portion of the wall is terminated with oxygen.

17. A microfluidic cell according to claim 1 , wherein the one or more quantum spin defects have a decoherence time T 2 equal to or greater than 0.1 ms, 0.1 ms, 0.3 ms, 0.6 ms, 1 ms, 5 ms, or 15 ms.