  Chirality, either of light or matter, has proved to be very practical in
biosensing and nanophotonics. However, the fundamental understanding of its
temporal dynamics still needs to be discovered. A realistic setup for this are
the so-called metastructures, since they are optically active and are built
massively, hence rendering an immediate potential candidate. Here we propose
and study the electromagnetic-optical mechanism leading to chiral optical
imprinting on metastructures. Induced photothermal responses create anisotropic
permittivity modulations, different for left or right circularly polarized
light, leading to temporal-dependent chiral imprinting of hot-spots, namely
imprinting of chirality. The above effect has not been observed yet, but it is
within reach of modern experimental approaches. The proposed nonlinear
chiroptical effect is general and should appear in any anisotropic material;
however, we need to design a particular geometry for this effect to be strong.
These new chiral time-dependent metastructures may lead to a plethora of
applications.
