Diode-pumped solid-state laser platform for compact and long-lasting strontium-based optical clocks.

Area of Science:

• Atomic Physics and Spectroscopy
• Laser Science and Photonics
• Materials Science for Quantum Technologies

Background:

• Strontium (Sr) atom and ion optical clocks are crucial for precise timekeeping.
• These advanced clocks rely on multiple narrow-band visible laser sources at specific wavelengths.
• Existing laser technologies face limitations in providing all necessary wavelengths for Sr clocks.

Purpose of the Study:

• To report on the development of a solid-state laser source operating at key wavelengths for Sr optical clocks.
• To investigate the potential of Pr³⁺:LiGdF₄ (Pr:GLF) as a versatile laser medium in the deep-red spectral region.
• To assess the spectral tunability of the Pr:GLF laser for broader applicability.

Main Methods:

• Demonstrated diode-pumped continuous-wave laser operation of a single Pr:GLF crystal.
• Achieved laser output at specific wavelengths: 674, 688, 689, 698, and 707 nm.
• Investigated the spectral tunability of the Pr:GLF laser system.

Main Results:

• Successful continuous-wave laser operation of Pr:GLF at multiple critical wavelengths (674-707 nm).
• Identified Pr:GLF as the only known active medium for solid-state lasers covering all required deep-red wavelengths for Sr clocks.
• Achieved an uninterrupted spectral tuning range of 17 nm (697-714 nm).

Conclusions:

• Pr³⁺:LiGdF₄ is a highly promising material for developing compact and robust solid-state laser sources for strontium optical clocks.
• The demonstrated laser performance and tunability offer a significant advancement for next-generation timekeeping technologies.
• This work paves the way for more accessible and stable Sr-based optical clock systems.