Speaker
Description
Optical nonreciprocity refers to the phenomenon where light in a system behaves differently depending on its direction of propagation. We aim to create a low-loss nonreciprocal phase-shifting element which has different optical path length depending on propagation direction. When placed in a ring cavity, the asymmetry would create a difference between the optical path lengths for the counterpropagating waves, resulting in different resonance conditions for counterpropagating waves inside the cavity. Thus the cavity can support two distinct frequencies of light counterpropagating while both are on resonance inside the cavity. The interference of two counterpropagating waves at different frequencies will create a moving optical lattice, which can be used to trap and transport atoms. We present multiple proposed designs with different materials and mechanisms to achieve nonreciprocity, and a theoretical comparison between their performances. These mechanisms include combinations of the Faraday effect, stress-induced birefringence, Brewster’s angle, and anti-reflective coatings. We measured relevant optical properties of these proposed materials such as fused silica and terbium gallium garnet. We present prototypes of the nonreciprocal element as well as our investigations of their performance, such as optical loss, stability and tunability. Finally, we discuss the advantages, limitations, and practical challenges of each approach in creating the low-loss nonreciprocal phase-shifting element.
| Keyword-1 | Optical nonreciprocity |
|---|---|
| Keyword-2 | Faraday rotation |