Nonlinear and quantum optics with structured light beams

• Grant number: 25/11919-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - General Physics
• Principal Investigator: Rafael Ferreira Pinto do Rego Barros
• Grantee: Henrique Vieira dos Santos Guerra
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/08450-0 - StruQT - Deploying Structured light for Quantum Technologies, AP.QUTIA.JP

Abstract

The nonlinear interaction between light beams is a widely explored mechanism in quantum technologies. For example, pairs of entangled photons are produced through spontaneous parametric down-conversion, while the detection of single photons is assisted by sum-frequency generation. However, such nonlinear processes are subject to constraints imposed by phase matching in the nonlinear medium, which requires engineering the medium through periodic inversion of ferroelectric domains. In this project, we propose a new way to control second-order nonlinear interactions without domain inversion. Our proposal consists of replacing domain inversion with the spatial and temporal structuring of the interacting beams. In particular, we will use this connection between domain inversion and the spatial structure of the beams as a resource to control the quantum state generated in parametric down-conversion, aiming to create entangled states in polarization and frequency in a simplified manner. (AU)