A pulse detector amplifier is disclosed. The pulse detector amplifier may have a detection switching leg that receives an input energy pulse. The pulse detector may have a mirror fast trigger including a trigger node and controlling a mirrored switching leg. The detection switching leg may trigger the trigger node in response to the input energy pulse. The pulse detector amplifier may also have a mirrored switching leg that controlled by the trigger node. The mirrored switching leg may control a voltage and/or current on the output node responsive to the input energy pulse. Thus, the pulse detector may generally include a cascode architecture, with a mirror fast trigger (which may include a FET) between the mirrored legs of the amplifier and enhancing the rapid triggering of the amplifier output. Thus the pulse detector may be power efficient, may have a small part count, and may be sensitive.