All-Optical Radio-Frequency Phase Detection for Rydberg Atom Sensors Using Oscillatory Dynamics.

Area of Science:

• Atomic physics
• Quantum sensing
• Electromagnetics

Background:

• Rydberg atom sensors offer high-precision electromagnetic field measurements with broad bandwidth.
• Current methods often rely on radio-frequency (RF) heterodyning for phase readout, requiring complex RF equipment.
• The sensor typically acts as a square-law detector for RF electric field strength.

Purpose of the Study:

• To investigate an all-optical phase-sensitive detection scheme for Rydberg atom sensors.
• To eliminate the need for a radio-frequency local oscillator in phase measurements.
• To enable comprehensive RF signal characterization (phase, frequency, amplitude) using only optical components.

Main Methods:

• Utilized a five-level closed-loop excitation scheme in Rydberg atoms.
• Introduced finite detuning in the loop fields to induce atomic response oscillations.
• Transferred the oscillatory atomic response to a probe laser absorption signal.

Main Results:

• Demonstrated that atomic response oscillates at the detuning frequency of the loop fields.
• Showed that the probe laser absorption signal carries these oscillations.
• Successfully imprinted RF signal phase, frequency, and amplitude onto the oscillatory dynamics.

Conclusions:

• The all-optical phase-sensitive detection scheme is effective for Rydberg atom sensors.
• This method allows for precise RF field measurement without external RF local oscillators.
• Demodulation and matched filter techniques can extract RF signal parameters from the probe transmission.