Nanoscale scanning sensors
A sensing probe may be formed of a diamond material comprising one or more spin defects that are configured to emit fluorescent light and are located no more than 50 nm from a sensing surface of the sensing probe. The sensing probe may include an optical outcoupling structure formed by the diamond material and configured to optically guide the fluorescent light toward an output end of the optical outcoupling structure. An optical detector may detect the fluorescent light that is emitted from the spin defects and that exits through the output end of the optical outcoupling structure after being optically guided therethrough. A mounting system may hold the sensing probe and control a distance between the sensing surface of the sensing probe and a surface of a sample while permitting relative motion between the sensing surface and the sample surface.
1. A method of forming a sensing probe formed of a diamond material, the method comprising:
providing a diamond material comprising one or more spin defects configured to emit fluorescent light; and
forming an optical outcoupling structure formed by the diamond material and etched by a weak oxygen plasma etch, the optical outcoupling structure configured to optically guide the fluorescent light emitted by the one or more spin defects toward an output end of the optical outcoupling structure, wherein the weak oxygen plasma etch is at an etching temperature less than 150 degrees Celsius and at an RF power less than 150 W, so that the one or more spin defects are located no more than 50 nm from a sensing surface of the sensing probe, and a decoherence time of the one or more spin defects is greater than 10 μsec; and
wherein the sensing probe including the optical outcoupling structure is formed of a diamond component having at least one linear dimension greater than 1 μm in length.
2. The method of claim 1 , wherein the one or more spin defects are located no more than 40 nm, 30 nm, 20 nm, 15 nm, 12 nm, or 10 nm from the sensing surface of the sensing probe.
3. The method of claim 1 , wherein the one or more spin defects are NV − (nitrogen-vacancy) defects.
4. The method of claim 1 , comprising forming the sensing probe including the optical component of a single crystal diamond material.
5. The method of claim 1 , wherein a decoherence time of the one or more spin defects is greater than 10 μsec, 50 μsec, 100 μsec, 200 μsec, 300 μsec, 500 μsec, or 700 μsec.
6. The method of claim 1 , comprising forming the optical outcoupling structure by any one of a nanopillar; an immersion lens, and via internal reflection.
7. The method of claim 6 , wherein the optical outcoupling structure is formed of a nanopillar.
8. The method of claim 7 , wherein the nanopillar has a diameter between 100 nm and 300 nm, and a length between 0.5 μm and 5 μm.
9. The method of claim 1 , wherein the sensing probe comprises no more than 50, 30, 10, 5, 3, 2, or 1 spin defects located no more than 50 nm from the sensing surface and optically coupled to the optical outcoupling structure.
10. The method of claim 1 , wherein the sensing probe comprises more than 50 spin defects in the form of a layer located no more than 50 nm from the sensing surface and optically coupled to the optical outcoupling structure.