Fundamental limit to cavity linewidth narrowing with single atoms

• Grant number: 22/05551-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2022
• End date: December 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Physics - Atomic and Molecular Physics
• Principal Investigator: Celso Jorge Villas-Bôas
• Grantee: Lucas Ribeiro da Silva Santos
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Optical cavities in the Fabry-Perot configuration work out as resonators for the electromagnetic field, whose line width depends on the natural properties of the mirrors involved (transmission and reflection coefficients, and absorption rates) and the distance between them. However, it is possible to modify the line width of an optical cavity using the phenomenon of electromagnetically induced transparency (EIT). This phenomenon has been highlighted due to its numerous applications mainly in the areas of quantum information and sensor development. As the name suggests, this phenomenon consists of making an atomic medium transparent to a given radiation field (probe field), via the application of a second field, known as the control field. When the atomic system is placed inside an optical cavity, its line width can be changed by adjusting the control field strength, allowing to obtain optical cavity line widths much narrower than their natural line width when atomic vapors with many atoms are employed. This narrowing has an immediate application, which is the manufacture of frequency filters adjustable by external fields. However, in the single-atom regime, there is a fundamental limitation to this narrowing of the line width, since in this regime quantum fluctuations cannot be disregarded. With this in mind, in the present project, we will investigate how the line width of an optical cavity changes when it has a defined number of atoms inside it. We will also investigate how the line-width behaves as a function of other system parameters such as atom-cavity coupling and intensities of the probe and control fields.(AU)