High visibility Hong-Ou-Mandel interference via a time-resolved coincidence measurement.

Area of Science:

• Quantum Information Processing
• Quantum Optics
• Photonics

Background:

• High visibility Hong-Ou-Mandel (HOM) interference is crucial for photonic quantum information processing.
• Standard HOM experiments often use pulse-pumped spontaneous parametric down conversion (SPDC) and large detection time windows.
• Continuous wave (cw)-pumped SPDC with small detection windows is advantageous for reducing background noise.

Purpose of the Study:

• To address distortions in HOM visibility measurements caused by background noise in previous continuous wave (cw) experiments.
• To present a novel method for unbiased treatment of background noise in cw-SPDC HOM experiments.
• To experimentally demonstrate high-visibility HOM interference using heralded telecom photons generated via cw-SPDC.

Main Methods:

• Utilized continuous wave (cw) pump light for spontaneous parametric down conversion (SPDC) to generate photon pairs.
• Employed time-resolved coincidence measurements with small detection time windows to minimize background noise.
• Developed and applied a new method for calculating HOM visibility that accounts for cw backgrounds without bias.

Main Results:

• Demonstrated a high visibility Hong-Ou-Mandel (HOM) interference.
• Achieved an observed HOM visibility of 0.87 ± 0.04.
• The achieved visibility is comparable to results obtained using pulse-pumped SPDC photons.

Conclusions:

• The new method provides accurate HOM visibility measurements in the presence of cw backgrounds.
• High-visibility HOM interference is achievable with heralded telecom photons generated by cw-SPDC.
• This work advances quantum information processing techniques using photonic entanglement.