Induced transparency: interference or polarization?

TL;DR

This paper distinguishes between polarization-induced transparency and electromagnetically induced transparency in optical systems, revealing polarization mismatch as a cause of narrow transparency windows and exploring their coexistence for light manipulation.

Contribution

It clarifies the physical origins of polarization induced transparency versus EIT and demonstrates their coexistence in optical resonator systems.

Findings

Polarization mismatch can induce narrow transparency windows resembling EIT.

PIT originates from polarization rotation effects and is unidirectional.

Coexistence of PIT and EIT offers new light manipulation methods.

Abstract

The polarization of optical fields is a crucial degree of freedom in the all-optical analogue of electromagnetically induced transparency (EIT). However, the physical origins of EIT and polarization induced phenomena have not been well distinguished, which can lead to confusion in associated applications such as slow light and optical/quantum storage. Here we study the polarization effects in various optical EIT systems. We find that a polarization mismatch between whispering gallery modes in two indirectly coupled resonators can induce a narrow transparency window in the transmission spectrum resembling the EIT lineshape. However, such polarization induced transparency (PIT) is distinct from EIT: it originates from strong polarization rotation effects and shows unidirectional feature. The coexistence of PIT and EIT provides new routes for the manipulation of light flow in optical resonator systems.