EXTREME ULTRAVIOLET LIGHT GENERATION DEVICE AND METHOD FOR CONTROLLING EXTREME ULTRAVIOLET LIGHT GENERATION DEVICE

An extreme ultraviolet light generating apparatus includes a laser device, a target detector, and a controller. The laser device emits a pulsed laser beam. The target detector detects a target substance supplied as an application target for the laser beam to the inside of a chamber. The controller controls the laser device based on a burst signal in which a burst period and an idle period are repeated. In the burst period, an extreme ultraviolet light beam has to be generated. In the idle period, the generation of the extreme ultraviolet light beam has to be paused. When a size of a target substance detected at the target detector in the idle period is greater than a predetermined size, the controller may reduce an intensity of a laser beam entering the inside of the chamber from the laser device.