| 摘要 |
PURPOSE:To obtain the optical disk which is high in the dependency of the reflection factor on the intensity of incidence by using a reflecting film which is made of a tertiary nonlinear optical material with a prescribed, refractive index and has a prescribed multiple reflection factor and prescribed film thickness. CONSTITUTION:The reflecting film of the optical disk having a 1st transmission film, the reflecting film, and a 2nd transmission film which are laminated in turn has center light intensity I0 and peripheral part light intensity Ie and is consisted of the tertiary nonlinear optical material which has a refractive index etaII = eta0+eta2.Iin (eta0: linear refractive index, eta2: nonlinear refractive index) for a laser beam spot having an intensity distribution Iin shown by a Bessel function. Further, the film has the multiple reflection factor R shown by an equation I and film thickness (h) within a range shown by an expression II (eta I: refractive index of the 1st transmission film, eta III: refractive index of the 2nd transmission film, lambda: wavelength of incident laser beam). This constitution improves the reflection factor-light intensity dependency of the reflecting film and the optical disk which whose reflection factor has high dependency on the incident light intensity can be obtained. |
