Nanophotonics for quantum optics using nitrogen-vacancy centers in diamond

Area of Science:

• Quantum optics
• Materials science
• Nanotechnology

Background:

• Efficient quantum communication requires interfaces between quantum systems, like nitrogen-vacancy centers in diamond, known for long spin coherence lifetimes.
• Optical microcavities and waveguides are crucial for mediating this communication.

Purpose of the Study:

• To report progress in fabricating low-loss, small-mode-volume optical microcavities coupled to diamond.
• To explore hybrid systems for on-chip quantum network integration.

Main Methods:

• Fabrication and characterization of silica microdisks coupled to diamond nanoparticles.
• Fabrication and characterization of gallium phosphide microdisks coupled to single-crystal diamond.
• Theoretical proposal for a gallium phosphide nanowire photonic crystal cavity coupled to diamond.

Main Results:

• Demonstrated progress in realizing hybrid microcavity systems for diamond integration.
• Silica microdisks offer easier fabrication and testing.
• Gallium phosphide microdisks coupled to bulk diamond show potential for long-term spectral stability and on-chip integration.

Conclusions:

• Both silica and gallium phosphide hybrid systems show potential for quantum applications.
• Gallium phosphide coupled to bulk diamond is a promising candidate for future integrated photonic quantum networks due to enhanced spectral stability at low temperatures.