Narrow Optical Linewidths in Stoichiometric Layered Rare-Earth Crystals.

Area of Science:

• Quantum Information Science
• Materials Science
• Solid-State Physics

Background:

• Rare-earth emitters are key for quantum memory but dopant-based methods introduce disorder and limit emitter density.
• Stoichiometric materials offer high emitter densities and narrow optical linewidths, enabling quantum information processing and collective effects.

Purpose of the Study:

• To investigate the potential of stoichiometric crystalline materials for quantum memory applications.
• To characterize the optical and spin properties of NaEu(IO_{3})_{4} for integrated quantum technologies.

Main Methods:

• Fabrication and characterization of the layered stoichiometric crystalline material NaEu(IO_{3})_{4}.
• Optical spectroscopy to measure inhomogeneous and homogeneous linewidths.
• Spectral hole-burning techniques to determine hyperfine spin lifetime and demonstrate atomic frequency comb delay.

Main Results:

• Observed narrow optical linewidths in NaEu(IO_{3})_{4}: inhomogeneous linewidth of 2.2(1) GHz and homogeneous linewidth of 120(4) kHz.
• Measured a hyperfine spin lifetime of 1.9(4) s using spectral hole-burning.
• Demonstrated an atomic frequency comb delay of up to 800 ns, showing potential for quantum signal processing.

Conclusions:

• NaEu(IO_{3})_{4} is a promising stoichiometric material for efficient, long-lived quantum memory.
• The material's properties are well-suited for integration into scalable quantum photonic technologies.
• Regular emitter spacing in stoichiometric materials facilitates advanced quantum information processing and exploration of collective effects.