Precision dual-comb spectroscopy using wavelength-converted frequency combs with low repetition rates

Area of Science:

• Quantum Optics
• Spectroscopy
• Laser Physics

Background:

• Precision spectroscopy has been vital for quantum mechanics and is crucial in modern fields like fundamental physics and medical diagnostics.
• Optical frequency combs are essential tools for establishing the frequency axis in precision spectroscopy.
• Dual-comb spectroscopy offers enhanced resolution compared to traditional Fourier-transform infrared spectrometers.

Purpose of the Study:

• To demonstrate dual-comb spectroscopy in the visible-wavelength region.
• To achieve high spectral resolution using wavelength-converted frequency combs.
• To establish a reliable and maintenance-free spectroscopic method for visible wavelengths.

Main Methods:

• Utilized two Er-doped fiber frequency combs with slightly different repetition rates (19.8 MHz).
• Employed wavelength conversion to generate combs in the visible spectrum.
• Performed dual-comb spectroscopy and analyzed the spectral shape of molecular iodine.

Main Results:

• Successfully demonstrated dual-comb spectroscopy in the visible-wavelength region.
• Achieved relatively high spectral resolution due to the low repetition rates of the combs.
• Observed spectral shapes that closely matched theoretical fitting based on molecular iodine's hyperfine structure.

Conclusions:

• Dual-comb spectroscopy using wavelength-converted Er-doped fiber combs is a reliable and maintenance-free technique.
• This method provides high resolution and is applicable to various experiments in the visible spectrum.
• The study validates the potential of this approach for advancing precision measurement and fundamental physics.