Voltage-Controllable Second-Order Susceptibility in Arsenic Sulfide Film

Electric field induced second harmonic (EFISH) generation on arsenic sulfide films deposited via thermal evaporation is investigated, demonstrating a strong voltage-controllable second-order optical susceptibility (chi((2))). Surprisingly, even at 0 V, a non-EFISH bulk chi((2)) is also revealed. Supplementary polarization- and angle-dependent SHG measurements on as-deposited films show Maker fringe patterns from which the components of the chi((2)) tensor are determined. Calibrating the observed second harmonic generation (SHG) intensity from the arsenic sulfide against the SHG from a classic beta barium borate (BBO) crystal, a main component of chi((2)) zzz = 0.22 pm/V at 0 V is ascertained. Adding a dc-electric field during the EFISH-measurements the chi((2)) rises and reaches a maximum value of chi((2))(zzz) = 13,5 pm/V at the electric breakdown field strength of 102 MV/m. This EFISH-enhanced chi((2))(zzz)-value surpasses the chi((2)) main components of traditional nonlinear crystals, such as KDP, LBO or BBO significantly. This and a high intrinsic third order susceptibility of chi((3)) approximate to 5x10(-20) m(2)/V-2 makes arsenic sulfide an interesting material for nonlinear hybrid photonic applications.