| abstract |
The object of the present invention is to provide an optically functional element having a large change in refractive index with temperature change and a fast change rate in refractive index, a production method for the same and optical switch, temperature sensor and optical information recording medium using the same.The present invention provides a thin film formed directly on a substrate or via other layers, and the film is composed of particles with an average diameter of not larger than 13 nm, observed at film surface. The present invention also provides an optically functional element having an amount of change in refractive index of not less than 2.0x10<-4>/° C. The present invention further provides a production method for said thin film by sputtering under reduced pressure in an inert gas atmosphere containing 3-15% by volume of oxygen, and optical switch, temperature sensor and optical information recording medium using said element. |