Dissipative Kerr solitons in optical microresonators

Shrinking optical metrology The ability to generate laser frequency combs—light sources comprising equidistant laser lines spanning a large range of wavelengths—has revolutionized metrology and precision spectroscopy. The past decade has seen frequency combs being generated in optical microresonator circuits, offering the prospect of shifting precision metrology applications from the realm of national laboratories to that of everyday devices. Kippenberg et al. review the development of microresonator-generated frequency combs and map out how understanding and control of their generation is providing a new basis for precision technology. Science , this issue p. eaan8083