Fig. 1. Schematic diagram of experimental setup for femtosecond laser induced ferroelectric domain inversion

Fig. 2. Schematic diagram of experimental setup for second-harmonic generation observation

Fig. 3. （a） Schematic diagram of Cerenkov-type second-harmonic generation modulated by transverse reciprocal lattice vector，（b） and（c） distribution and participation of reciprocal lattice vectors in Cerenkov-type second-harmonic generation modulated by random domains（b） and square lattice constitute by laser induced domains（c）（the arrows in（b） represent random reciprocal lattice vectors，black arrows are reciprocal lattice vectors contribute to phase match process，gray arrows are reciprocal lattice vectors which have no contribution in phase match process），（d） and（e） typical frequency doubled patterns in far field generated by spontaneous domains（d） and square lattice constitute by laser induced domains（e）（the color is artificial for better visualization）

Fig. 4. Threshold power of femtosecond laser for domain inversion depends on crystal temperature

Fig. 5. Schematic diagram of femtosecond laser induced domain inversion mechanism：（a） spontaneous domains in as-grown SBN crystal；（b） thermoelectric field induced by laser focus inside the crystal，red arrows represent thermoelectric field lager than coercive field，white arrows are thermoelectric field lower than coercive field；（c） distribution of inverted domain and spontaneous domains，the domain marked by red square is inverted by femtosecond laser