Towards a Compact Single-Diode-Pumped Ti:Sapphire Astrocomb

Frequency combs are a versatile technology comprising a sequence of regularly spaced, ultra-narrow, drift-free optical frequencies for a range of applications, including astronomy, metrology and spectroscopy. When referenced to an atomic standard, such as a Rb-disciplined oscillator, they can provide traceable optical frequencies with precision at the 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup> level. The demand for simple and compact optical frequency combs for use as atomically-referenced wavelength calibrators for astronomy [1], [2], particularly where spectral coverage at shorter wavelengths is needed [3], can be satisfied by supercontinuum generation followed by mode filtering from 1 GHz Ti:sapphire lasers [4], however commercial sources are relatively complex and expensive, limiting Ti:sapphire-based astro-combs from widespread adoption. Here, we present a route to a complete astrocomb based on a compact, diode-pumped 1 GHz Kerr-lens-modelocked Ti:sapphire laser and a Si3N4 waveguide [5], to generate an octave-spanning supercontinuum, which can be stabilised to create a turnkey and affordable calibration source for astronomy.