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Polarization-based truncated SU(1,1) interferometer based on four-wave mixing in Rb vapor
Optics Letters
|July 7, 2020
Summary
We developed a novel interferometer for measuring quantum fields, achieving significant noise reduction below the shot-noise limit. This method confirms entanglement and enhances common noise suppression for precise quantum measurements.
Area of Science:
- Quantum optics
- Quantum information science
Background:
- Two-mode squeezed vacuum fields are crucial for quantum information processing.
- Measuring joint-quadratures of these fields is essential for detecting entanglement and quantum noise.
Purpose of the Study:
- To propose and demonstrate a polarization-based interferometer for measuring optical joint-quadratures.
- To achieve quantum noise suppression below the shot-noise limit.
- To confirm entanglement in two-mode squeezed vacuum fields.
Main Methods:
- Utilizing a polarization-based truncated SU(1,1) interferometer.
- Employing a single balanced homodyne detector for measurements.
- Analyzing intensity-difference and phase-sum joint-quadratures.
Main Results:
- Demonstrated up to ≈2 dB quantum noise suppression below the shot-noise limit.
- Confirmed entanglement between the two quantum fields.
- Observed flat joint-quadrature squeezing and entanglement across a wide frequency range (hundreds of Hz to several MHz).
Conclusions:
- The proposed interferometer effectively measures joint-quadratures and suppresses common noise.
- This technique enables robust observation of quantum squeezing and entanglement.
- The method offers a practical approach for advanced quantum optical measurements.
