Laser frequency combs—extraordinarily precise tools for measuring frequencies (or colors) of light—have helped propel advances in timekeeping, trace gas detection and related physics research to new heights in the past decade. While typical lasers operate at only a single or handful of frequencies, laser frequency combs operate simultaneously at many frequencies, approaching a million for some combs. These combs have very fine, evenly spaced "teeth," each a specific frequency, which can be used like hash marks on a ruler to measure the light emitted by lasers, atoms, stars or other objects. But frequency combs are usually bulky, delicate lab instruments—about the size of a typical suitcase—and challenging to operate, which limits their use.
