Orbiting planets induce a weak radial velocity (RV) shift in the host star that provides a powerful method of planet detection. Importantly, the RV technique provides information about the exoplanet mass, which is unavailable with the complementary technique of transit photometry. However, RV detection of an Earth-like planet in the ‘habitable zone' requires extreme spectroscopic precision that is only possible using a laser frequency comb (LFC). Conventional LFCs require complex filtering steps to be compatible with astronomical spectrographs, but a newchip-based microresonator device, the Kerrsoliton microcomb, is an ideal match for astronomical spectrograph resolution and can eliminate these filtering steps. We demonstrate an atomic/molecular line-referenced soliton microcomb for calibration of astronomical spectrographs. These devices can ultimately provide LFC systems that would occupy only a few cubic centimetres, thereby greatly expanding implementation of these technologies into remote and mobile environments beyond the research lab.
For an introduction to this subject see the following work: