Hans Butler is a part-time professor in the Control Systems group of the Department of Electrical Engineering at Eindhoven University of Technology. He specializes in lithographic scanner control, an area of expertise he has built through a long career at ASML, where he is also a Fellow. Butler is a specialist in dynamics and control systems. 

As a control engineer, Butler has worked at ASML on multiple components of lithographic tools, such as handlers, illuminators, projection systems and stages. Within ASML's Mechatronic Systems Development Department, he has led groups working on actuators, opto-mechatronics, and vibration isolation and damping. Butler is an ASML fellow with dynamics and control as main focus area, in particular in relation to the imaging process. Improving the positioning accuracy from a perspective of dynamics and control has always been the guiding interest throughout his career.