Spectral control of broadband laser for pumping cold molecules

Author(s)

Jaime Javier Borges Marquez

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 2025-07-11

Examining board members

Luis Gustavo Marcassa; Claudio Lenz Cesar; Marcio Heraclyto Gonçalves de Miranda

• Advisor: Luis Gustavo Marcassa

Abstract

Laser cooling cannot be easily applied to molecules because they generally do not have closed optical transitions, as in atomic systems. Their complex internal structure, which includes vibration and rotation, prevents well-established cooling and deceleration techniques in atomic physics from being applied to molecular systems, except for a very restricted class of molecules. In this dissertation, we explore rovibrational pumping techniques applied to molecular cooling, using the rubidium (Rb2) molecule as an example. To this end, we propose and characterize two broadband laser systems with high spectral control for the selective excitation of allowed vibrational and rotational transitions. Both systems are based on optical systems that employ at least one dispersive element to spatially separate the spectral components of light in the Fourier plane, where a digital micromirror device (DMD) acts as an active spectral filter, allowing precise modeling of the pumping spectrum. The results obtained demonstrate the viability of the proposed systems for the selective manipulation of rovibrational states, evidencing their applicability in optical pumping schemes aimed at cooling molecules. (AU)

• FAPESP's process: 23/06732-5 - Broadband laser spectral control for pumping cold molecules
• Grantee: Jaime Javier Borges Marquez
• Support Opportunities: Scholarships in Brazil - Master