Abstract: Methods and apparatus are disclosed for the nonlinear generation of sum and difference frequencies of electromagnetic radiation propagating in a nonlinear material. A waveguide having a waveguide cavity contains the nonlinear material. Phase matching of the nonlinear generation is obtained by adjusting a waveguide propagation constant, the refractive index of the nonlinear material, or the waveguide mode in which the radiation propagates. Phase matching can be achieved even in isotropic nonlinear materials. A short-wavelength radiation source uses phase-matched nonlinear generation in a waveguide to produce high harmonics of a pulsed laser.

Abstract: Disclosed herein is a method for reducing the color of an emulsion of functionalized polyolefin wax by treating an emulsion with a water soluble oxidizing agent at a temperature above the freezing point and below the boiling point of the emulsion and below the softening point of the wax. Disclosed herein, also, is the essentially colorless emulsion produced according to the disclosed method which is useful as an additive to floor polishes and other coating products.