Discrete optics in femtosecond-laser-written photonic structures

Over the last few years arrays of evanescently coupled waveguides have been brought into focus as a particular representation of functionalized optical materials, in which the dispersion and diffraction of propagating light can be specifically tuned. Moreover, it turns out that the light evolution in these systems shares fundamental similarities to the quantum evolution of particle wavefunctions, so that waveguide arrays can act as a model system for emulating quantum mechanics. Recently, a novel technique was developed with which waveguides can be directly 'written' into various optical bulk materials using femtosecond laser pulses, which allows for the realization of a variety of innovative concepts which are not feasible using other fabrication methods. The aim of this tutorial is to give an introduction to this topic.