Optimizing two-dimensional tilted-front laser pulses for efficient terahertz generation

We developed a theory that describes terahertz generation with tilted-front femtosecond laser pulses in electro-optic crystals, a technique providing record experimental efficiencies nowadays. The theory accounts for the transverse size of the laser beam and allows us to explore the dependence of the conversion efficiency on laser focusing. We calculated the radiation patterns inside the crystal and studied the terahertz emission from the crystal. Two typical experimental situations - LiNbO₃ excited with Ti:sapphire laser at room and cryogenic temperatures - were considered. Our theory predicts optimal parameters of the laser pulse and crystal size maximizing the terahertz yield.