Mechanical Control of a Microrod-Resonator Optical Frequency Comb

``Microcombs,'' frequency combs based on optical microcavities, are small in size and low in power consumption. They are seen as a very attractive alternative to traditional optical frequency combs based on tabletop lasers. Now, experimentalists advance the development of microcombs in two important ways: simplifying and speeding up their fabrication to just under one minute and stabilizing their frequency spacing with a precision of 5×10⁻¹⁵ by controlling cavity modes with mechanical strain.