Approaching Maximal Precision of Hong-Ou-Mandel Interferometry with Nonperfect Visibility.

Area of Science:

• Quantum mechanics
• Quantum optics
• Quantum metrology

Background:

• Precision in quantum parameter estimation depends on measurement strategy.
• The quantum limit of precision is theoretically achievable under ideal conditions.
• Real-world experiments face limitations like imperfect visibility and losses.

Purpose of the Study:

• To model precision limits in two-photon Hong-Ou-Mandel interferometry under realistic conditions.
• To investigate the impact of nonperfect visibility and temporally unresolved measurements on precision.
• To determine how experimental precision approaches the quantum limit.

Main Methods:

• Developed a theoretical model for precision limits in two-photon Hong-Ou-Mandel interferometry.
• Utilized coincidence statistics to account for nonperfect visibility and unresolved measurements.
• Experimentally controlled visibility up to 99.5% using different quantum states.

Main Results:

• Precision scaling with visibility depends on the time-frequency phase space area of the probe state.
• Identified an optimal scaling for precision.
• Achieved a ratio of 0.97 between experimental precision and the quantum limit in the optimal scenario.

Conclusions:

• The study provides a practical model for understanding precision limits in quantum interferometry.
• Experimental results validate the theoretical model and establish a new benchmark for precision.
• Demonstrated that near-quantum-limited precision is achievable even with realistic experimental imperfections.