Locking a three-mirror optical cavity: A negative imaginary systems approach

In this paper, we present an example of control system design based on negative imaginary (NI) system theory. The system under consideration is an optical cavity system. A dynamical model of the cavity system is obtained through system identification of applied to experimental input output frequency response data obtained using a digital signal analyzer (DSA). The identified model satisfies NI property. An integral resonant controller is designed based on the NI system theory.