Laser ultrashort-pulse spectroscopy of the order parameters of hydrogen-bonded ferroelectrics

The change in the duration of an ultrashort laser pulse during its passage through a single crystal of a hydrogen-bonded ferroelectric is determined as a function of the temperature of this crystal and, consequently, of the order parameter. It is shown that, depending on this temperature, a pulse may become shorter or longer inside the crystal. This makes it possible to use such ferroelectrics in reducing the duration of ultrashort laser pulses. The temperature at which an increase in the pulse duration changes to a reduction is determined. The dependence of this temperature on the internal parameters of a ferroelectric is found.