# Custom-tailored spatial mode sorting by controlled random scattering

## TL;DR

This paper presents a novel method for customizing the sorting of arbitrary spatial light modes using controlled random scattering, enabling full access to encoded information while preserving coherence, with applications in quantum and classical photonics.

## Contribution

The authors introduce a new technique to tailor spatial mode sorting through phase preshaping of incident light, overcoming previous limitations in mode access and control.

## Key findings

- Successfully sorted various spatial modes into desired output channels
- Maintained coherence in complex mode transformations
- Demonstrated applicability to both classical and quantum information processing

## Abstract

The need to increase data transfer rates constitutes a key challenge in modern information-driven societies. Taking advantage of the transverse spatial modes of light to encode more information is a promising avenue for both classical and quantum photonics. However, to ease access to the encoded information, it is essential to be able to sort spatial modes into different output channels. Here, we introduce a novel way to customize the sorting of arbitrary spatial light modes. Our method relies on the high degree of control over random scattering processes by preshaping of the phase structure of the incident light. We demonstrate experimentally that various sets of modes, irrespective of their specific modal structure, can be transformed to any output channel arrangement. Thus, our method enables full access to all of the information encoded in the transverse structure of the field, for example, azimuthal and radial modes. We also demonstrate that coherence is retained in this complex mode transformation, which opens up applications in quantum and classical information science.