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