Abstract: The present invention relates to a method for the periodic domain inversion of ferroelectric flux-grown crystals that are low conductive or made low conductive. The invention also relates to an arrangement for monitoring the domain inversion of crystals while using a laser. The invention also relates to the use of crystals in applications of periodic domain inverted crystals, partly for generating light (electromagnetic radiation) at new wavelengths by non-linear optical frequency mixing (frequency doubling, difference frequency generation, summation frequency generation, optical parametric oscillation, etc.) and partly for electro-optical applications, such as light beam modulation, and partly for acoustic applications. such as the generation of acoustic waves from electric voltages applied across the crystal.

Abstract: A waveguide in optically nonlinear materials for quasi-phase-matched frequency conversion of electromagnetic waves, arranged in a crystal substrate. The waveguide includes a periodically alternating crystal orientation necessary for quasi-phase-matching. The crystal orientation is provided in the form of a periodically domain inverted structure of ferroelectric domains, with reversed crystal orientation in relation to intermediate regions located between the domains. The domain structure is achieved by use of a periodic mask structure applied to the surface of the substrate in combination with a subsequent heat treatment of the substrate.

Abstract: The present invention relates to a lensless spectrum analyzer, preferably of integrated optical type, with a radiation source (1) connected to a waveguide (2) which is connected to an electro-optical deflector (3), exploiting Pockel's effect. The radiation from the deflector (3) is guided by the waveguide (2) on to a detection matrix (4). The electro-optical deflector (3) then consists of an electrode matrix (5) with the electrodes (6-11) arranged in or in the vicinity of an electro-optically active material (21). The electrodes (6-11) which are of different widths and are disposed at different distances from each other are arranged along a line (18) which is largely disposed at right angle to the incident radiation. By this means, the deflector acquires lens properties and can perform the desired Fourier transformation of the electric signal connected to the deflector (3).