Swept dual-comb spectroscopy via common-mode cavity tuning and stabilization.

Area of Science:

• Spectroscopy
• Laser Physics
• Optical Engineering

Background:

• Dual-comb spectroscopy (DCS) offers high resolution but often requires complex setups.
• Improving the resolution and acquisition speed of DCS is crucial for advanced applications.

Purpose of the Study:

• To demonstrate common repetition rate sweeping in a single-cavity dual-comb laser.
• To enhance spectroscopy resolution and simplify the DCS implementation.

Main Methods:

• Utilized a single-cavity dual-comb laser with simultaneous repetition rate sweeping via piezoelectric modulation.
• Employed an Yb:CaF2 laser at a 1-GHz repetition rate for spectroscopy of low-pressure acetylene.
• Implemented active control of the spectroscopy comb and passive tracking of the second comb for stability.

Main Results:

• Achieved an effective spectroscopy resolution of 50 MHz within 0.8 seconds acquisition time.
• Obtained a normalized signal-to-noise ratio (SNR) of 20 dBHz.
• Demonstrated broad aliasing-free optical bandwidth exceeding 4 THz with phase tracking.
• Maintained long-term stability of radio-frequency (RF) comb line positions and one-to-one correspondence.

Conclusions:

• Single-cavity dual-comb spectroscopy with common repetition rate sweeping offers a simplified and efficient approach.
• This method provides a balance between resolution, simplicity, and acquisition speed.
• Presents a novel technique for implementing dual-comb spectroscopy systems.