Abstract: The present invention relates to a method to control the nucleation and transverse motion of 180° inverted domains in ferroelectric nonlinear crystals. It includes a process composing of a high temperature oxidation of the first metal layer and a pulsed field poling of the second electrodes. The main object of present invention is to provide domain inversion of ferroelectric nonlinear crystals with field control the nucleation and transverse motion of inverted domains and two-dimension nonlinear photonic crystals for time-domain multiple-wave simultaneous lasers and space filter function. Another object of present invention is to provide space-charge effect for screened edge field beneath the metal electrode, The other object of present invention is to provide the constraint of inverted domain nucleation in the oxidized electrode for arbitrarily geometrical form of 2D ferroelectric lattice structure.

Abstract: A method of forming oxide from nitride, in which the oxidation is enhanced by illuminating the nitride material with UV light. This method produces a rapid growth of oxide and allows for the monitoring of the oxide thickness in situ. The method comprises the steps of (i) placing the nitride material on an illuminating holder; (ii) dipping the nitride material and the illuminating holder in an electrolyte; and (iii) illuminating the nitride material with a light having an energy larger than the energy gap of the nitride material. The nitride material can be connected to a conductive electrode located in the electrolyte via a galvanometer to monitor a photo current generated by the oxidation of the nitride material so as to monitor the thickness of the oxide formed on the nitride material in situ. A metal coating can be coated on the nitride material to define the oxide forming region. The pH value of the electrolyte is in a range of approximately 3 to 10, and is preferably about 3.5.

Abstract: A method for etching nitride is provided, by which the etching rate and the roughness of the etching surface can be powerfully controlled, and by which the etching depth can be in-situ monitored. The etching method comprises the steps of: (i) coating a first electrode on a nitride chip; (ii) mounting the nitride chip on a holding device; (iii)dipping the holding device, the nitride chip and the first electrode in electrolysis liquid; (iv) irradiating the nitride chip with a UV light having a wavelength shorter than 254 nm; and (v) connecting the first electrode to a second electrode dipped in the electrolysis liquid by a galvanometer to in-situ monitor the etching current, so as to in-situ control the etching depth.