Light localization in photonic crystal waveguides

Contacts:

David Garcia Fernández, DTU Fotonik, (dgar@fotonik.dtu.dk)

Peter Lodahl, DTU Fotonik, 4525 3807 (peter.lodahl@fotonik.dtu.dk)

Quantum Photonics Group: http://www.fotonik.dtu.dk/quantumphotonics

Materials such as milk, clouds, and biological tissues owe their appearance to the way they interact with light. By multiple scattering of the incident beam, light performs a random walk through these materials and they become opaque. If the scattering is very pronounced, scattered light can be confined inside the system due to interference, forming so-called Anderson-localized modes. So far, localized modes have been analyzed in completely random systems, like powders, where no accurate control can be exerted over their properties, e.g., their energy or spatial extension. An alternative to control localization are composite nanostructures with a periodic modulation of the refractive index called photonic crystals. A waveguide, which works like an optical wire, can be engineered in the structure just by taken out a raw of holes. Anderson localized modes form spontaneously when the lattice is slightly disordered (see Figure). Such an effect has been observed very recently in these systems. In this master project you will study the phenomenon of Anderson localization in disordered PCW with accurately controlled disorder. You will work on and improve an experimental setup to characterize the spectral and spatial properties of Anderson localized modes which are still not fully understood. This project offers a unique possibility to combine two fields of hot research – photonic crystals and multiple scattering of light.

Light gets localized when is launched into photonic crystal waveguides (PCW) through an optical fibre. Due to light localization, scattered light from PCW shows strong fluctuations.

About us

We are around 10 dedicated researchers and students in The Quantum Photonics group. We continuously arrange social events such as running, football and lunch club and we have weekly group meetings/journal clubs where we discuss recent scientific breakthroughs in our field.