Abstract: The optical resonator as intends to generate coherent X-ray by irradiation of polarized laser interference fringes with electron beam has been unknown. The present invention provides an optical resonator that is capable of preparing polarization laser, polarization X-ray and coherent X-ray. The optical resonator is characterized by comprising an optical resonator that is capable of circulating two or more polarization lasers and irradiation of the polarization lasers with electron beam introduced by an electron beam feed port which is inserted in the intersection of laser paths inside the optical resonator.