Excimer laser apparatus

摘要

An excimer laser apparatus having a laser pulse width detecting device to avoid a short-pulse operation exerting a significant influence upon the lifetime of a lens system. The excimer laser apparatus has a laser pulse shape detecting device for detecting the laser pulse shape of laser light by receiving a part of the laser light. A laser pulse width calculating device calculates the laser pulse width of the laser light on the basis of laser pulse shape data from the laser pulse shape detecting device. A control device outputs an abnormality signal when it is judged from laser pulse width data from the laser pulse width calculating device that the laser pulse width is shorter than a predetermined length. <IMAGE>