Widely tunable and narrow-linewidth hybrid-integrated diode laser at 637 nm

Area of Science:

• Quantum Optics
• Laser Physics
• Materials Science

Background:

• Nitrogen-vacancy (NV) centers in diamond are crucial for quantum sensing and information processing.
• Stable and tunable laser sources are required to precisely address NV centers.
• Existing laser technologies may lack the required tunability, stability, or integration capabilities.

Purpose of the Study:

• To develop and characterize hybrid-integrated extended cavity diode lasers (ECDLs).
• To achieve tunability around 637 nm, targeting the zero-phonon line of NV centers.
• To demonstrate high performance in terms of tuning range, linewidth, and output power for quantum applications.

Main Methods:

• Hybrid integration of diode lasers with extended cavities.
• Achieving spectral coverage of 8 nm around 637 nm.
• Characterization of mode-hop-free tuning range (up to 97 GHz) and intrinsic linewidth (down to 10 kHz).
• Measurement of output power in single-mode fiber (2.5 mW) and on-chip (4.0 mW).

Main Results:

• Demonstrated hybrid-integrated ECDLs tunable around 637 nm with an 8 nm spectral coverage.
• Achieved mode-hop-free tuning up to 97 GHz and an intrinsic linewidth as narrow as 10 kHz.
• Obtained maximum output power of 2.5 mW in a single-mode fiber, with 4.0 mW on-chip.
• Successfully integrated and packaged lasers in standard housing with fiber pigtails.

Conclusions:

• The developed ECDLs meet critical requirements for addressing NV centers.
• The lasers offer high stability and performance suitable for integration into complex optical systems.
• This work advances the development of robust laser sources for quantum technologies.