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Updated: Jul 28, 2025
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Implementation of a Reference Interferometer for Nanodetection
Published on: April 26, 2014
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Sub-Hz relative linewidths from an interferometrically stabilized mid-infrared frequency comb
Optics Letters
|June 1, 2023
Summary
We measured the coherence of mid-infrared frequency combs generated via difference frequency generation (DFG). Our results show a sub-Hertz relative linewidth, demonstrating high precision for molecular spectroscopy applications.
Area of Science:
- Quantum Optics
- Spectroscopy
- Laser Physics
Background:
- Frequency combs are essential for high-precision molecular spectroscopy.
- Difference frequency generation (DFG) is a common method for creating mid-infrared combs.
- Coherence properties of DFG sources require further investigation.
Purpose of the Study:
- To investigate the coherence properties of a Raman-soliton based DFG mid-infrared frequency comb.
- To measure the relative phase noise and linewidth between DFG and Tm:fiber combs.
- To develop a method for long-term intensity noise suppression.
Main Methods:
- Utilized a Raman-soliton based DFG source driven by an Yb:fiber frequency comb.
- Performed heterodyne beat measurements between the DFG comb (near 4 µm) and a Tm:fiber comb (2 µm).
- Employed a new pump/seed delay locking mechanism based on interferometry.
Main Results:
- Measured the relative phase noise power spectral density of the two frequency combs.
- Achieved a sub-Hertz relative linewidth between the DFG comb and the Tm:fiber comb.
- Demonstrated long-term stable intensity noise suppression using the novel locking mechanism.
Conclusions:
- The DFG-based mid-infrared frequency comb exhibits excellent coherence properties.
- The developed measurement and stabilization techniques are crucial for advanced spectroscopic applications.
- This work advances the precision and stability of mid-infrared frequency comb sources.
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