Low-noise optomechanical single phonon-photon conversion for quantum networks

Area of Science:

• Quantum optics
• Nanotechnology
• Solid-state physics

Background:

• Optomechanical crystals (OMCs) interface mechanical modes with optical photons for quantum information distribution.
• Thermal mechanical noise in OMCs hinders the development of scalable quantum networks.

Purpose of the Study:

• To overcome thermal noise limitations in OMCs for quantum network applications.
• To generate high-purity single photons using a novel quasi-two-dimensional OMC design.

Main Methods:

• Utilized a quasi-two-dimensional optomechanical crystal (OMC).
• Generated single photons through single phonon-photon conversion.
• Performed Hanbury Brown-Twiss and Hong-Ou-Mandel interference experiments.
• Measured temporal wavepackets using two-photon interference.

Main Results:

• Achieved single photon generation with low thermal noise and high purity ($g^{\left(2\right)}\left(0\right)=0.35_{-0.08}^{+0.10}$).
• Demonstrated photon indistinguishability and coherence (V = 0.52 ± 0.15) after 1.43 km fiber delay.
• Observed narrow bandwidths as low as 10 MHz for optomechanically generated single photons.

Conclusions:

• The quasi-two-dimensional OMC effectively suppresses thermal noise, enabling high-quality single photon generation.
• Results support the development of multinode quantum networks and hybrid entanglement between mechanical oscillators and telecom quantum emitters.