Frequency comb spectroscopy is a recent field of research that has blossomed in the past five years. This Review discusses developments in the emerging and rapidly advancing field of atomic and molecular broadband spectroscopy with frequency combs.

It has recently been shown that optical solitons can form stably bound states, so-called soliton molecules. Here, Wang et al. demonstrate stable soliton molecule complexes and explore the different bonds represented by the inter- and intra-molecular coupling.

Integrating an optical Kerr frequency comb source with an electronically excited laser pump produces a battery-powered comb generator that does not require external lasers, moveable optics or laboratory set-ups.