UC Riverside

In this invited article, we report the experimental demonstration of the simultaneous coherent locking of two independent lasers with arbitrary multi-FSR (free spectral range) frequency separation to a Kerr microcomb soliton, resulting in the creation of synthetic microcomb soliton crystals. Each of the two pumps is self-injection-locked to its neighboring microcavity mode and acts as an arbiter linking the microcomb to the cavity. We show that the beating of the two pumps creates a manifest discrete symmetry and that certain microcomb states generated in this pumping scheme spontaneously break this symmetry, thereby realizing \emph{dissipative} discrete time crystals. Apart from introducing a powerful platform leveraging advanced photonics for the creation and scientific exploration of various types of dissipative time crystals and their properties, our results constitute a decisive step towards the two-point locking of Kerr microcombs with moderate bandwidths much smaller than an octave which cannot be self-referenced through standard approaches such as the f-2f technique.