Comb-mode sweeping in a 650 nm-1030 nm astrocomb

Area of Science:

• Astronomy and Astrophysics
• Optical Engineering

Background:

• Astrocombs offer stable, uniform calibration lines for astronomical spectrographs.
• Detector inhomogeneities necessitate characterization of the entire detector area for precise radial-velocity measurements.

Purpose of the Study:

• To demonstrate a novel astrocomb architecture capable of sweeping calibration lines in frequency.
• To improve spectrograph calibration for enhanced radial-velocity precision, aiding exoplanet detection.

Main Methods:

• Utilized Fabry-Pérot filtering of a primary comb (1 GHz spacing).
• Employed feed-forward locking to overlap a single-frequency laser onto selected comb lines.
• Demonstrated operation across a broad wavelength range (650-1030 nm).

Main Results:

• Achieved a tunable astrocomb architecture with swept frequency increments.
• Demonstrated continuous system performance exceeding 12 hours, indicating long-term stability.
• Provided fine sampling of the spectrograph instrument function.

Conclusions:

• The demonstrated astrocomb architecture fulfills the requirement for interrogating the entire detector area.
• This technology offers the necessary stability and fine sampling for achieving high radial-velocity precision.
• The system supports the detection of Earth-like exoplanets by enabling precise radial-velocity measurements.