Density effects on light scattering by cold atomic samples measured by diffusing wave spectroscopy

• Grant number: 24/21830-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: March 31, 2027
• Field of knowledge: Physical Sciences and Mathematics - Physics - Atomic and Molecular Physics
• Principal Investigator: Raul Celistrino Teixeira
• Grantee: Daniel Siqueira Coelho
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

This master's project aims to numerically and experimentally investigate the transport of light in dense atomic media through the diffusing wave spectroscopy technique applied to light scattered from a cold atomic sample. Preliminary numerical results show that the modification of transport, going from diffusive to partially coherent when the sample density is increased, is captured by the first-order temporal correlation function of the scattered light, which is the observable considered by diffusing wave spectroscopy. The master's student will implement an apparatus for measuring the temporal correlation function, characterize it, and apply it to light scattered by a cold and dense sample of 88Sr atoms, produced in an existing experimental apparatus. Numerical work in parallel will allow the interpretation of experimental results, with the aim of deriving from these results scaling laws and qualitative changes in the microscopic transport of quasi-resonant light in this high density regime, when the mean free path approaches the wavelength of light. This work will aim at identifying signatures of coherent transport in the sample, and advancing the debate about the existence or not of 3D Anderson localization of light.