  "Flying focus" techniques produce laser pulses with dynamic focal points that
travels distances much greater than a Rayleigh length. The implementation of
these techniques in laser-based applications requires the design of optical
configurations that can both extend the focal range and structure the radial
group delay. This article describes a method for designing optical
configurations that produce ultrashort flying focus pulses with
arbitrary-trajectory focal points. The method is illustrated by several
examples that employ an axiparabola for extending the focal range and either a
reflective echelon or a deformable mirror-spatial light modulator pair for
structuring the radial group delay. The latter configuration enables rapid
exploration and optimization of flying foci, which could be ideal for
experiments.
