Synthetic diamond materials for quantum and optical applications and methods of making the same

A synthetic diamond material comprising one or more spin defects having a full width half maximum intrinsic inhomogeneous zero phonon line width of no more than 100 MHz,

• wherein the full width half maximum intrinsic inhomogeneous zero phonon line width is averaged over one or both of:
• at least 10 seconds;
• and at least 10 spectral scans,
• wherein the synthetic diamond material is chemical vapor deposited (CVD) synthetic diamond material, and
• wherein the one or more spin defects are negatively charged nitrogen vacancy (NV−) spin defects, and
• wherein the one or more spin defects are located no more than 1 μm from a surface of the synthetic diamond material.

A synthetic diamond material comprising one or more spin defects having a full width half maximum intrinsic inhomogeneous zero phonon line width of no more than 100 MHz,

• wherein the full width half maximum intrinsic inhomogeneous zero phonon line width is averaged over one or both of:
• at least 10 seconds;
• and at least 10 spectral scans,
• wherein the synthetic diamond material is chemical vapor deposited (CVD) synthetic diamond material, and
• wherein the one or more spin defects are negatively charged nitrogen vacancy (NV−) spin defects,
• wherein the synthetic diamond material comprises a layer of said spin defects, the layer comprising at least 105 spin defects/cm2 and having a thickness no more than 1 μm, and
• wherein the thickness of said layer is no more than 100 nm.

A synthetic diamond material comprising one or more spin defects having a full width half maximum intrinsic inhomogeneous zero phonon line width of no more than 100 MHz, and

• one or more photonic structures fabricated in the synthetic diamond material,
• wherein the full width half maximum intrinsic inhomogeneous zero phonon line width is averaged over one or both of:
• at least 10 seconds;
• and at least 10 spectral scans,
• wherein the synthetic diamond material is chemical vapor deposited (CVD) synthetic diamond material, and
• wherein the one or more spin defects are negatively charged nitrogen vacancy (NV) spin defects, and
• wherein the one or more spin defects are located no more than 1 μm from the one or more photonic structures or within the one or more photonic structures.

A method of fabricating a synthetic diamond material, the method comprising:

• selecting a synthetic diamond material comprising a single substitutional nitrogen concentration of no more than 100 ppb;
• and
• annealing the synthetic diamond material using a multi-stage annealing process comprising:
• a first annealing step at a temperature in a range 350 to 450° C. for at least 2 hours;
• a second annealing step at a temperature in a range 750 to 900° C. for at least 2 hours;
• and
• a third annealing step at a temperature in a range 1150° C. to 1550° C. for at least 2 hours;
• said synthetic diamond comprising
• one or more spin defects having a full width half maximum intrinsic inhomogeneous zero phonon line width of no more than 100 MHz,
• wherein the full width half maximum intrinsic inhomogeneous zero phonon line width is averaged over one or both of:
• at least 10 seconds;
• and at least 10 spectral scans,
• wherein the synthetic diamond material is chemical vapor deposited (CVD) synthetic diamond material, and
• wherein the one or more spin defects are negatively charged nitrogen vacancy (NV−) spin defects.