Asymmetric comb waveguide for strong interactions between atoms and light.

Area of Science:

• Quantum optics and nanophotonics
• Atomic physics and quantum information science

Background:

• Strong light-matter interactions are crucial for quantum technologies.
• Coupling quantum emitters like cold atoms with nanophotonic structures, such as optical waveguides, is a key area of research.

Purpose of the Study:

• To propose and investigate a new type of periodic dielectric waveguide for enhanced atom-photon interactions.
• To engineer an unusual dispersion relation and electric field distribution for optimal light-matter coupling.

Main Methods:

• Design of an asymmetric comb waveguide.
• Computation of optical trapping potentials using guided modes.
• Analysis of atomic interaction with the waveguide's electric field and dispersion.

Main Results:

• The asymmetric comb waveguide supports a slow mode with quartic dispersion and an extended electric field.
• Cold Rubidium atoms were trapped in a 1.3-mK-deep potential well at 100 nm from the structure.
• A high beta factor (0.88) and a 10x increased radiative decay rate into the slow mode were achieved at a group velocity of c/50.

Conclusions:

• The proposed asymmetric comb waveguide offers unprecedented control over light-matter interactions.
• This system demonstrates significant potential for applications in quantum information processing and quantum simulation.
• The engineered dispersion and field profile are highly effective for trapping cold atoms and enhancing photon emission into guided modes.