So far, the techonology to make the surface of the optical element smooth to supress the scattering. Scattering reduces the available optical energy and causes the noise. On the contrary, we try to use the scattering effect in the engineering applications. For this purpose, we have to develop a method to control the scattering. The key technology is the fabrication method of articifical scattering media. One of the developed fabrication method is to use a femtosecond laser proceesing. By focusing the femtosecond laser light into a transparent medium such as glass or polymer, the micrometer-sized void can be fabricated. By creating the voids in random position in the transparent medium, the fabricated medium can be worked as the scattering medium. The possible applications of the artifical scattering medium are optical security and the fabrication of phantom of human tissues.
Optical setup of fabricating the scattered medium by using fs-laser processing and its results