  Spatial heterogeneity and phase competition are hallmarks of
strongly-correlated materials, promising tunable functionality on the
nanoscale. Light-induced switching of a correlated insulator to a metallic
state is well established. However, optical excitation generally lacks the
specificity to select sub-wavelength domains and control final textures. Here,
we employ valley-selective photodoping to drive the domain-specific quench of a
textured Peierls insulator. Polarized excitation leverages the anisotropy of
quasi-one-dimensional states at the correlated gap to initiate an
insulator-to-metal transition with minimal electronic heating. We find that
averting dissipation facilitates domain-specific carrier confinement, control
over nanotextured phases, and a prolonged lifetime of the metastable metallic
state. Complementing existing manipulation schemes, valley-selective
photoexcitation will enable the activation of electronic phase separation
beyond thermodynamic limitations, facilitating optically-controlled hidden
states, engineered heterostructures, and polarization-sensitive percolation
networks.
