Two-dimensional bound states of ultrashort light pulses and polarisation of light in ferroelectric impurity crystals

The polarisation evolution of a ferroelectric crystal after its illumination by ultrashort laser pulses is described theoretically and numerically by using the microscopic pseudospin formalism. Parameters are found for which quasi-two-dimensional long-lived states can exist in ferroelectrics. For different initial conditions, the dynamics of bound states of the electromagnetic field and polarisation of the crystal is presented and properties of ferroelectrics with impurities and without them are compared.