MARKING METHOD AND EQUIPMENT, AND MARKED OPTICAL MEMBER

摘要

PROBLEM TO BE SOLVED: To provide a marking method capable of easily recognizing an existence of a marking without using a special reading equipment and also capable of avoiding a destruction of material and a deterioration of material strength. SOLUTION: A transparent glass substrate 1 is provided for a marking object. A laser beam with a wavelength capable of permeating a material forming the transparent glass substrate 1 is focused inside the transparent glass substrate 1 so as to cause a multiphoton absorption. A focusing position of the laser beam is moved so that a range of a changed refractive index caused by the multiphoton absorption can provide for a diffraction pattern causing a visible light to diffract.