Something that transmit low light intensities whereas blocks high light intensity intensities.

Perhaps the plasma mirror can transmit low-intensity light whereas reflect high-intensity light.

A saturable absorber is an optical component with a certain absorption loss for light, which is reduced at high optical intensities. Such nonlinear absorption can occur, e.g., in a medium with absorbing dopant ions, when a strong optical intensity leads to depletion of the ground state of these ions. Similar effects can occur in semiconductors, where excitation of electrons from the valence band into the conduction band reduces the absorption for photon energies just above the band gap energy.

@Akeel m. Kadim, thanks, actually I wanted the opposite phenomenon. Something that doesn't absorb at low light, is there something commercially

available?

Please find out for liquid saturate absorbers such as dyes in the literature where this feature can be controlled.