Controlled bistable operation of an FM mode-locked Nd:YAG laser

It is well known that there are two possible phase positions for the pulse in a mode-locked laser with an internal phase modulator. By using a modulator cut in the form of a Brewster angle prism, it becomes possible to operate an Nd:YAG laser stably in either position at will. The angular beam deflection is slightly different for the two modes and, hence, by mirror adjustment one mode or the other can be selected. A simple analysis is presented to estimate the magnitude of this effect in rough agreement with experimental observations.