We discuss the application of stress-induced changes in the crystal of a monolithic Nd:YAG laser as a possibility for
micro force measurement. In fact, the application of an unknown force on the resonator-amplifier of a laser, formed by a
transparent photo elastic material, can lead to a change of the laser frequency by as much as several gigahertz depending
on the force intensity. In addition, the rates of change of the two orthogonally polarizations of the same mode with
applied force are different. Hence, the strength of the applied force can be deduced from frequency measurement of the
beat signal between the two polarizations of the oscillating mode or between the mode polarized in the orthogonal
direction of the force and a reference frequency of a stabilized laser.