Frequency-comb-referenced tunable diode laser spectroscopy and laser stabilization applied to laser cooling

Area of Science:

• Atomic, Molecular, and Optical Physics
• Spectroscopy
• Laser Physics

Background:

• Optical clocks require stable light sources with precise absolute frequencies for laser cooling of trapped atoms and ions.
• Frequency combs are essential components of optical clocks and can stabilize tunable diode lasers.

Purpose of the Study:

• To develop a stable, precisely tuned light source for laser cooling of trapped strontium ions.
• To demonstrate the stabilization of a diode laser to a frequency comb for high-precision applications.

Main Methods:

• Stabilizing a distributed-feedback semiconductor laser to a frequency comb.
• Utilizing simple electronics for laser locking and scanning across comb lines.
• Resolving frequency comb mode number ambiguities using a saturated absorption cell with known hyperfine lines.

Main Results:

• Achieved megahertz-level stability and absolute frequency for the diode laser.
• Successfully demonstrated a method for stabilizing a diode laser to a frequency comb.
• Developed a technique for resolving frequency comb mode ambiguities.

Conclusions:

• The described technique provides a simple, fast, and wide-tuning method for stabilizing diode lasers.
• This approach is suitable for laser cooling of trapped strontium ions.
• The technique has potential for broader applications in precision spectroscopy.