All-optical input-agnostic polarization transformer via experimental Kraus-map control

TL;DR

This paper introduces an all-optical polarization transformer that can convert any input polarization state to a fixed output state without regard to the input, using experimental Kraus-map control, enabling new polarization stabilization techniques.

Contribution

It experimentally demonstrates the first complete kinematic state controllability of an open single-qubit via Kraus maps, enabling input-agnostic polarization transformation.

Findings

Successfully transforms all input polarization states to a fixed output state.

Operates passively without requiring active control.

Potential applications in polarization stabilization for ultrafast optics.

Abstract

The polarization of light is utilized in many technologies throughout science and engineering. The ability to transform one state of polarization to another is a key enabling technology. Common polarization transformers are simple polarizers and polarization rotators. Simple polarizers change the intensity depending on the input state and can only output a fixed polarized state, while polarization rotators rotates the input Stokes vector in the 3D Stokes space. We experimentally demonstrate an all-optical input-agnostic polarization transformer (AI-APT), which transforms all input states of polarization to a particular state that can be polarized or partially polarized. The output state of polarization and intensity depends solely on setup parameters, and not on the input state, thereby the AI-APT functions differently from simple polarizers and polarization rotators. The AI-APT is completely passive, and thus can be used as a polarization controller or stabilizer for single photons and ultrafast pulses. To achieve this, we, for the first time, experimentally realize complete kinematic state controllability of an open single-qubit by Kraus maps put forth in [Wu et al. J. Phys. A 40, 5681 (2007)]. The AI-APT may open a new frontier of partially polarized ultrafast optics.