2ND-HARMONIC GENERATION IN SMECTIC-A PHASE OF FERROELECTRIC LIQUID-CRYSTAL INDUCED BY ELECTROCLINIC EFFECT

Second-harmonic generation (SHG) of ferroelectric liquid crystal (FLC) has been studied in the smectic A (Sm A) phase in 4'-(1-butoxycarbony l-1-ethoxy)-3'-nitrophenyl 4-[4-(omega-alkenyloxy)phenyl]benzoate (1BC 1ENPAPB) with large electroclinic (EC) effect and a large spontaneous polarization. Type I phase-matching has been observed in the angular d ependence of SHG intensity in the Sm A phase. SHG intensity caused by the EC effect is proportional, to the square of applied electric field , and it has been found that the effective optical coefficient is prop ortional to electric field.