Optical rogue waves on demand

Among the myriad of nonlinear optical effects, supercontinuum generation is perhaps the most visually stunning and useful in applications ranging from tomography to frequency metrology. When a high-intensity optical pulse propagates through a nonlinear dielectric medium, its spectrum broadens, with the degree of broadening depending on the strength of the interaction. If the interaction is strong enough (i.e., the interaction length is long or the intensity is high enough), then this spectral broadening can be dramatic, resulting in a supercontinuum (SC) whose width can include the entire visible spectrum. While SC can be produced in many different ways, the most common way today is to use a photonic crystal fiber, which has a small core to confine the light, resulting in a high intensity and low loss, allowing for long interaction lengths [1]. Despite the ease of generating SC, the dynamics behind it are extremely complicated, involving a cascade of different nonlinear effects. In a paper appearing in Physical Review Letters[2], Daniel Solli and Bahram Jalali from the University of California, Los Angeles, with Claus Ropers from the University of Göttingen in Germany have gone a long way towards clarifying the role that various nonlinear effects play. More importantly, they have shown that it is possible to control the relative importance of different nonlinear interactions, giving researchers control over the bandwidth and coherence properties of the supercontinuum, effectively allowing it to be used in ever more sophisticated ways.