Comb-locked cavity ring-down spectrometer.

Area of Science:

• Spectroscopy
• Cavity-Ring-Down Spectroscopy
• Laser Spectroscopy

Background:

• High-precision molecular spectroscopy is crucial for various scientific applications.
• Existing methods often face limitations in accuracy, sensitivity, or spectral range.

Purpose of the Study:

• To develop and demonstrate a novel comb-locked cavity-ring-down spectrometer.
• To achieve extreme frequency accuracy and high sensitivity in the near-infrared region (1.5-1.63 μm).

Main Methods:

• Utilized a novel comb-locked cavity-ring-down spectrometer.
• Employed tight frequency locking of a probe laser to an optical frequency comb.
• Integrated efficient light injection into a length-swept high-finesse passive cavity.
• Performed spectroscopic tests on a carbon dioxide (CO2) absorption line.

Main Results:

• Achieved extreme frequency accuracy and high sensitivity in the near-infrared spectrum.
• Demonstrated a line center frequency accuracy of ~17 kHz for a CO2 line.
• Attained a limit of detection as low as 5.7 × 10(-11) cm(-1) over a single scan.
• Ensured high reproducibility and accuracy of the frequency axis by scanning the comb repetition rate.

Conclusions:

• The novel spectrometer offers a significant advancement in high-precision gas analysis.
• The demonstrated accuracy and sensitivity pave the way for enhanced spectroscopic measurements.
• This technique is suitable for applications requiring precise molecular detection and characterization.