The invention provides a photodetector. The photodetector comprises: an optical sensor, a first electrode and a second electrode which are connected with the optical sensor, and a first electrode leader and a second electrode leader. One end of the first electrode leader and one end of the second electrode leader are separately connected with the first electrode and the second electrode, and the other ends are as outputs. The optical sensor is produced by metal or alloy materials. The photodetector of the invention can rapidly respond to laser pulse with fs pulse width in ultraviolet or infrared band. The width of generated voltage pulse can be less than 0.5 nanosecond and pulse full width is only several nanoseconds.