# Optically controlled orbital angular momentum generation in a polaritonic quantum fluid

## TL;DR

This paper proposes a semiconductor polaritonic quantum fluid source capable of generating and controlling specific orbital angular momentum states of light, with unique flow patterns arising from modulational instabilities.

## Contribution

It introduces a novel micron-sized source based on polaritonic quantum fluids that can spontaneously generate and control OAM components through modulational instabilities.

## Key findings

- Spontaneous formation of OAM components not in the pump laser.
- Exotic flow patterns with generation-annihilation pairs.
- Control of modulational instabilities in polaritonic systems.

## Abstract

Applications of the orbital angular momentum (OAM) of light range from the next generation of optical communication systems to optical imaging and optical manipulation of particles. Here we propose a micron-sized semiconductor source which emits light with pre-defined OAM components. This source is based on a polaritonic quantum fluid. We show how in this system modulational instabilities can be controlled and harnessed for the spontaneous formation of OAM components not present in the pump laser source. Once created, the OAM states exhibit exotic flow patterns in the quantum fluid, characterized by generation-annihilation pairs. These can only occur in open systems, not in equilibrium condensates, in contrast to well-established vortex-antivortex pairs.