Amorphous glasses can exhibit second-order susceptibilities if the material’s inversion symmetry is broken by treatments such as poling or electron-beam irradiation. Recent experiments have shown that chalcohalide glasses, in particular, may have sufficient second-order nonlinearity to eliminate the need for expensive nonlinear crystals, and to integrate frequency conversion and electro-optic modulation directly into optical fibers and planar waveguides.The experiments, reported by scientists at East China University of Science and Technology in Shanghai and at Kyoto University in Japan, were the first to create a clear second-harmonic wave in chalcohalide glasses containing large amounts of alkali ions. The scientists polled the ∼millimeter-thick samples by clamping them between electrodes and applying voltages of several hundred volts per millimeter.Optics Letters, Dec. 1, 2006, pp. 3492-3494.