| 摘要 |
This invention is concerned with materials for nonlinear optical devices for the conversion of optical energy at one frequency to optical energy at another frequency. Laser techniques have been developed so that it is possible to obtain a limited number of fundamental frequencies of coherent laser light by utilizing solid, gas, and liquid media. However, in many applications, laser light having frequencies not among the fundamental frequencies obtainable is required, and in some cases laser light exhibiting a continuous spectrum over a certain range of frequencies is required. Inorganic materials have been used extensively for nonlinear optical applications. However, they are only of limited use because of their bandwidth limitations. The possibility of using organic materials in nonlinear optical devices has generated much interest recently because a large number of organic materials are available for investigation and because they do not have the bandwidth limitations of inorganic materials. This invention provides devices comprising a laser source of coherent light radiation at a fixed fundamental frequency, a crystalline N,N'-substituted barbituric acid that crystallizes in a non-centrosymmetric configuration, means for directing the output radiation of the laser onto the N,N'-substituted barbituric acid, and output means for utilizing the second harmonic frequency. |
