Determination of the optimum orientation of an SC-cut resonator using a pulsed laser

A method which has been developed to measure the force-frequency effect in stress compensated (SC)-cut resonators by the use of a pulsed light beam from an excimer laser which is directed onto the vibrating surface of the device is described. The crystal resonance is maintained by a phase-locked loop with a long time constant, and the phase across the crystal is monitored. The small phase change is measured by the use of a lock-in amplifier which is locked to the repetition rate of the laser. The resulting measurement gives a determination of both the phase and the amplitude of the force-frequency effect. Several devices which have been produced with crystallographic orientations spanning the theoretical value are discussed. These were measured using the laser pulsing method. The frequency modulation is plotted against angle