Polymethine materials with solid-state third-order optical susceptibilities suitable for all-optical signal-processing applications

Judicious substitution of chalcogenopyrylium-terminated polymethine dyes with sterically demanding groups ameliorates the deleterious effects of aggregation on the optical properties of these materials in the solid state, facilitating high-number-density films that exhibit an unprecedented combination of nonlinear optical properties with low linear and nonlinear losses.