Exploiting the VO2 metal-insulator transition in nanoscale optical devices

The demonstration of a photo-induced insulator-to-metal transition in vanadium dioxide (VO₂) on a picosecond time scale in the mid-1990s foreeshadowed application of this photo-induced phase transition in silicon photonics devices. The talk introduces our current understanding of the phase-transition physics, but focuses on our recent demonstrations of sub-picosecond switching of cw and ultrafast signal pulses in silicon and silicon nitride waveguides. Direct in-line modulation of signal pulses achieves only modest contrast ratios. However, similar switching strategies deploying VO₂ on resonant structures promise substantially higher contrast with smaller switching energies in silicon photonic structures with micron-scale form factors.