14 GHz visible supercontinuum generation: calibration sources for astronomical spectrographs

Area of Science:

• Photonics
• Optical Engineering
• Astronomy

Background:

• Broadband optical sources are crucial for various applications, including astronomical spectroscopy.
• Photonic crystal fibers (PCFs) offer unique properties for nonlinear optical phenomena and spectral broadening.

Purpose of the Study:

• To design and demonstrate a tapered photonic crystal fiber (PCF) for generating a broadband visible optical spectrum.
• To investigate the potential of this PCF-based system for precision calibration of astronomical spectrographs.

Main Methods:

• Utilized a specially designed tapered PCF.
• Employed a frequency-doubled Ytterbium (Yb) fiber laser as the pump source (14 GHz repetition rate, sub-5 pJ pulses).
• Experimentally optimized the core diameter and performed numerical simulations to understand spectral generation mechanisms.

Main Results:

• Achieved a broadband optical spectrum spanning the visible range with a width of 235 nm.
• Identified optimal core diameter for spectral broadening.
• Numerical simulations elucidated the underlying physical mechanisms responsible for the observed spectral features.

Conclusions:

• The developed tapered PCF system effectively generates a broadband visible spectrum.
• The high repetition rate and broad spectrum make it suitable for calibrating astronomical spectrographs.
• This technology offers a promising solution for enhancing the precision of astronomical observations.