Second‐order optical nonlinearity in corona‐poled glass films

Several experiments were performed to elucidate the origin of the second‐order optical nonlinearity χ(2) induced in the corona‐poled Corning 7059 glass films. The values and the time decay of the second‐harmonic coefficient d33 were measured for the glass films poled on several different kinds of substrates. The value of d33 was found to be dependent on the kinds of substrates. It was also observed that the glass films poled on a soda‐lime substrate showed faster time decay of d33 than those poled on a Pyrex glass substrate. The glass films were also poled at room temperature, and the values of d33 were measured as a function of poling time. As a result, the value of d33 increased with the poling time and approached a value which was close to that obtained for the glass films poled at 100 °C. From the experimental results, it is speculated that the space charge formed in the vicinity of the interface between the glass film and the substrate contributes to the creation of the χ(2). The planar charge densit...