Signal distortion awakened from optical memory estimated using a calculation method with spatiotemporal separation

Area of Science:

• Optics and Photonics
• Quantum Information Science
• Materials Science

Background:

• Photonic storage and retrieval are crucial for all-optical networks.
• Photon echo (PE) based optical memories suffer from signal distortion, including waveform variation and temporal drift.
• Understanding the origin of these distortions is essential for improving optical memory fidelity.

Purpose of the Study:

• To investigate the fundamental cause of signal distortion in photon echo optical memories.
• To differentiate between true signal distortion and artifactual changes in recovered optical signals.
• To provide insights into the radiation mechanism in inhomogeneous broadening media for accurate signal recognition.

Main Methods:

• Numerical calculation utilizing spatiotemporal separation.
• Analysis of the asynchronous evolution of macroscopic population difference and dipole moments.
• Investigation of phase shifts and constructive interference during photon emission.

Main Results:

• Asynchronous evolution of population difference and dipole moments causes real echo signal distortion via phase shifts.
• Constructive interference of dipoles at the in-phase point induces photon emission, leading to waveform changes and temporal shifts.
• These observed changes are identified as false signal distortions, not true signal degradation.

Conclusions:

• The study elucidates the physical mechanism behind signal distortion in PE optical memories.
• Accurate recognition of temporal drift and waveform variation in recovered optical signals is achievable.
• Findings offer a new perspective on the radiation mechanism in inhomogeneous broadening media for enhanced optical memory performance.