Steady-State Ultracold Plasma Created by Continuous Photoionization of Laser Cooled Atoms

Area of Science:

• Atomic, Molecular, and Optical Physics
• Plasma Physics
• Quantum Simulation

Background:

• Ultracold plasmas are crucial for studying complex many-body interactions.
• Previous methods faced challenges in achieving stable, controllable plasma states.
• Strongly coupled plasmas offer insights into fundamental physics phenomena.

Purpose of the Study:

• To develop a method for creating steady-state ultracold plasmas with tunable densities and temperatures.
• To establish a controllable platform for investigating strongly coupled plasma physics.
• To explore the potential for achieving extremely strong coupling in ultracold plasma systems.

Main Methods:

• Utilized continuous two-step optical excitation of calcium atoms.
• Employed a magneto-optical trap for atom confinement and cooling.
• Analyzed plasma parameters using laser-induced fluorescence of calcium ions.

Main Results:

• Successfully prepared a steady-state ultracold plasma with a peak ion density of 2.7×10^6 cm^-3.
• Achieved a minimum electron temperature close to 2 K.
• Experimental results were accurately described by a theoretical model of hydrodynamical ion outflux and three-body recombination.

Conclusions:

• The developed steady-state approach enables the creation of tunable ultracold plasmas.
• The combination of steady-state conditions and magnetic confinement facilitates extremely strong coupling.
• This research provides a valuable platform for exploring fundamental many-body physics in plasmas.