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In the six decades since F. J. Morin’s seminal paper describing the insulator-to-metal transition (IMT) in vanadium dioxide (VO2) appeared, it has been cited more than three thousand times and touched off a search for electronic applications – such as the Mott transistor – that continues up to the present. Photonic applications are now also emerging as studies of ultrafast dynamics in the photo-induced phase transition (PIPT) have yielded an increasingly nuanced, microscopic understanding of the dynamics of the IMT in thin films and nanoparticles of VO2. It appears that VO2 can function as a virtually universal phase-changing oxide, especially for those photonic applications requiring low energy and high switching efficiency. Moreover, the large changes in the VO2 dielectric function can be leveraged to control plasmonic and phononic responses through the use of resonant and other field-enhancing structures. This introduces a critical element of reconfigurability on time scales ranging upwards from the sub-picosecond domain across a broad variety of hybrid structures. After highlighting key elements of the ultrafast dynamics triggered by the PIPT, I will review recent and unpublished applications of the PIPT in the near and mid-infrared to (1) switching in silicon photonics, (2) controlling hyperbolic phonon polaritons in hexagonal boron nitride, (3) constructing plasmonic memory and color arrays, and (4) designing reconfigurable arrays for imaging and sensing. For many applications, the optical losses require that one use as little VO2 as possible, highlighting the critical importance of future materials engineering as well as PIPT studies in nanostructures of sub-micrometer dimensions.
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