Dynamics of Supercontinuum Generation from Light Filaments in Ceramic Nd:YAG Polycrystals

Among the various materials used for supercontinuum generation, Nd:YAG ceramics and crystals exhibit exceptional efficiency and potential for use in, for instance, nonlinear imaging [1], [2]. In this work, we study wave collapse due to the intriguing spatiotemporal propagation effects possible in Nd:YAG. Beam collapse in nonlinear bulk media can be stabilized by several mechanisms, including conical emission, colinear and non-colinear supercontinuum generation, and plasma defocusing [3], [4]. As the beam propagates, plasma effects occur in nonuniformly-spaced focusing-defocusing cycles [2], [5], [6], in which a particular parameter plays a significant role: the electron collision time (proportional to conductivity) [2]. Supercontinuum generation accompanies beam collapse after only a millimeter-scale propagation distance, preventing the different wavepackets from dispersing significantly. Therefore, such light sources support interesting applications in nonlinear spectroscopy such as multiplex-CARS, as we have recently shown in Refs. [1], [2].