Steering and monitoring the light-driven motion of electrons inside matter on the time-scale of a single optical cycle is a key challenge in ultrafast light wave electronics and laser-based material processing. Physicists from the Max Born Institute in Berlin and the University of Rostock have now revealed a so-far overlooked nonlinear optical mechanism that emerges from the light-induced tunneling of electrons inside dielectrics. For intensities near the material damage threshold, the nonlinear current arising during tunneling becomes the dominant source of bright bursts of light, which are low-order harmonics of the incident radiation. These findings, which have just been published in Nature Physics, significantly expand both the fundamental understanding of optical non-linearity in dielectric materials and its potential for applications in information processing and light-based material processing.
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Source: Phys.org