Laser durability evaluation method and selection method for ferroelectric fluoride crystals

摘要

P To provide a method of simply evaluating laser durability of a ferroelectric substance fluoride crystal to laser with a wavelength in the UV/VUV region and to provide a method of selecting the ferroelectric substance fluoride crystal using the same. PSOLUTION: The method of evaluating laser durability of a ferroelectric substance fluoride crystal includes the steps of irradiating a crystal to be measured consisting of a ferroelectric substance fluoride crystal with an energy ray with a wavelength Measuring initial transmittance T1 when the energy ray transmits through the crystal to be measured and irradiating the crystal to be measured with ArF excimer laser of energy density 5-100 (mJ/(cmSP2/SP pulse)) or KrF excimer laser in 10SP4/SPpulses or greater and irradiating the crystal with the energy ray with the wavelength Measuring transmittance T2 after laser irradiation when the energy ray transmits through the crystal and calculating the decreasing rate (%) of the transmittance of the crystal by calculation equation (1): decreasing rate (%) of the transmittance = (T1-T2) /T1 100, using the T1 and T2. Then and the laser duration of the crystal to be measured is evaluated by the value of the decreasing rate of the transmittance. PCOPYRIGHT: (C)2010 and JPO& INPIT