Classical Dynamics of a Thin Moving Mirror Interacting with a Laser

We analyze the classical dynamics of a system composed of a one-dimensional cavity with a perfect, fixed mirror and a movable mirror with non-zero transparency interacting with a monochromatic laser. The movable mirror can deviate far from an equilibrium position, it is assumed to be thin so that it is modelled by a delta function, and we use the exact modes of the complete system. The transparency and the mirror-position dependent cavity resonance frequencies are built into the modes and this allows us to deduce that the radiation pressure force comes from a periodic potential with period half the wavelength of the field. The exact modes and the radiation pressure potential allow us to give intuitive physical interpretations of the dynamics of the system and to obtain approximate analytic solutions for the motion of the mirror. Three regimes are identified depending on the intensity of the field and it is found that the dynamics can be qualitatively very different in each of them with some regimes being very sensitive to the values of the parameters. Moreover, we determine conditions when the Maxwell-Newton equations used to describe the system constitute accurate approximations of the exact equations governing the dynamics.