All-optical reversible single-photon isolation at room temperature.

Area of Science:

• Quantum optics
• Atomic physics
• Quantum information science

Background:

• Nonreciprocal devices are crucial for quantum technologies.
• Magneto-optical isolators are unsuitable for magnetic-sensitive or on-chip quantum information processing.
• All-optical isolation at the quantum level at room temperature remains a significant challenge.

Purpose of the Study:

• To propose and experimentally demonstrate all-optical nonreciprocal isolation at room temperature.
• To achieve isolation for single photons and coherent optical fields.
• To overcome the limitations of existing magneto-optical devices.

Main Methods:

• Utilizing electromagnetically induced transparency (EIT) in warm atomic systems.
• Employing a Raman transition in the same experimental setup.
• Characterizing isolation and insertion loss for single photons and coherent light.

Main Results:

• Achieved high isolation (22.52 ± 0.10 dB) and low insertion loss (1.95 dB) for single photons.
• Demonstrated isolation with a bandwidth up to hundreds of megahertz.
• Showcased the ability to reverse the isolation direction for coherent optical fields using the Raman regime.

Conclusions:

• The proposed all-optical isolation methods are effective for single photons and coherent light at room temperature.
• These advancements offer a promising solution for simpler reconfiguration of high-speed classical and quantum information processing.
• The demonstrated techniques pave the way for more robust and versatile quantum technologies.