Phase-contrast imaging of a dense atomic cloud.

Area of Science:

• Atomic physics
• Optical imaging

Background:

• Characterizing dense atomic clouds is crucial for quantum simulations and atom optics.
• Traditional imaging methods struggle with high optical depths and spatial densities.
• Phase-contrast imaging (PCI) offers a potential solution for in situ density measurements.

Purpose of the Study:

• To demonstrate the reliability of phase-contrast imaging (PCI) for dense atomic clouds.
• To investigate the accuracy of PCI under extreme spatial and optical densities.
• To explore the impact of collective effects on atomic response in PCI.

Main Methods:

• Utilized phase-contrast imaging (PCI) with a spatial light modulator for flexible parameter control.
• Experimentally created dense cold atomic clouds of 88Sr atoms with high spatial densities (up to 7.9 × 10^13 atoms/cm^3) and optical depths (up to 64).
• Quantified the accuracy of the single-atom polarizability model in dense regimes and compared PCI results with time-of-flight measurements.

Main Results:

• PCI successfully reconstructed in situ density profiles for highly dense atomic samples.
• The imaging technique demonstrated robustness against artifacts and adaptability to experimental conditions.
• Excellent agreement between PCI and time-of-flight measurements was achieved, even at maximum densities.

Conclusions:

• Phase-contrast imaging (PCI) is a reliable and versatile tool for characterizing dense atomic clouds.
• The use of spatial light modulators enhances PCI's flexibility and adaptability.
• PCI provides accurate density measurements in regimes where collective effects might be significant.