Directional control of weakly localized Raman from a random network of fractal nanowires

TL;DR

This paper demonstrates how to control the out-of-plane directionality of coherent Raman light in a fractal nanowire network, revealing insights into light transport in disordered media and enabling advanced optical device development.

Contribution

It introduces a method to tune and visualize the directional emission of Raman light in a disordered nanowire network, advancing understanding of light transport in complex media.

Findings

Controlled out-of-plane Raman emission achieved

Real-space microscopy reveals light transport mechanisms

Potential for novel optical device applications

Abstract

Disordered optical media are an emerging class of materials capable of strongly scattering light. Their study is relevant to investigate transport phenomena and for applications in imaging, sensing and energy storage. While such materials can be used to generate coherent light, their directional emission is typically hampered by their very multiple scattering nature. Here, we tune the out-of-plane directionality of coherent Raman light scattered by a fractal network of silicon nanowires. By visualizing Rayleigh scattering, photoluminescence and weakly localized Raman light from the random network of nanowires via real-space microscopy and Fourier imaging, we gain insight on the light transport mechanisms responsible for the material's inelastic coherent signal and for its directionality. The possibility of visualizing and manipulating directional coherent light in such networks of nanowires opens venues for fundamental studies of light propagation in disordered media as well as for the development of next generation optical devices based on disordered structures, inclusive of sensors, light sources and optical switches.