# Acousto-Optic Modulation in Ambient Air

**Authors:** Yannick Schrödel, Claas Hartmann, Tino Lang, Jiaan Zheng, Max Steudel, Matthias Rutsch, Sarper H. Salman, Martin Kellert, Mikhail Pergament, Thomas Hahn-Jose, Sven Suppelt, Jan Helge Dörsam, Anne Harth, Wim P. Leemans, Franz X. Kärtner, Ingmar Hartl, Mario Kupnik, Christoph M. Heyl  
**arXiv:** [2304.06579](https://arxiv.org/abs/2304.06579)  
**Date:** 2023-04-13  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.06579v1/

## Key points

- Controlling the intensity, shape, direction and phase of coherent light is fundamental to photonics
- Modern laser optics often have limitations due to absorption or damage caused by solid media
- Gas media tailored by high-intensity ultrasound waves can overcome these limitations for versatile gas-phase Sono-Photonic methods
- Researchers achieved peak powers of 20 GW using this approach, exceeding the limits of solid-based acousto-optical modulation by about three orders of magnitude
- This breakthrough opens up new possibilities for controlling photons through gas media tailored by high-intensity ultrasound waves
- Could lead to significant advancements in fields such as optical communications, sensing and imaging.

## Summary

The ability to control the intensity, shape, direction and phase of coherent light is a fundamental aspect of photonics. However, modern laser optics often require parameter regimes where either the wavelength or the optical power restricts control due to absorption or damage. These limitations are imposed by the properties of solid media that most photonic control schemes rely on. To overcome these limitations, researchers propose using gas media tailored by high-intensity ultrasound waves for versatile gas-phase Sono-Photonic methods - gas-based photonic systems controlled by sonic waves. In a recent study published in arXiv, researchers demonstrate a first implementation of this approach by modulating ultrashort laser pulses using ultrasound waves in ambient air without any transmissive solid media. The researchers achieved peak powers of 20 GW exceeding the limits of solid-based acousto-optical modulation by about three orders of magnitude while preserving excellent beam quality and reaching a diffraction efficiency greater than 50%. The basic characteristics of gas-phase acousto-optic modulation involve using a fiber-coupled mode-locked laser as the light source for experimental demonstration. The laser delivers ultrashort pulse durations at a repetition rate of 100 MHz with an average power up to 10 W. The ultrasound resonator used in this study consists of two parallel plates separated by an adjustable distance filled with ambient air. This breakthrough opens up new possibilities for controlling photons through gas media tailored by high-intensity ultrasound waves and could lead to significant advancements in fields such as optical communications, sensing and imaging.