Generation of the Two Pure Modes of Transverse Ultrasonic Waves in an x-Cut Quartz Bar at 9.4 GHz

The two pure transverse modes of ultrasonic waves along the x direction were generated in an x-cut quartz bar by use of a TE110 cavity with an inhomogeneous electric field which was produced by a metal post of off-axial cut. The sound velocities of transverse waves were (3.18±0.01) and (4.95±0.05)×105 cm/sec, and that of the longitudinal wave was (5.59±0.01)×105 cm/sec at 4.2°K. The elastic stiffness constants of quartz crystal at 4.2°K are estimated, by use of the density 2.65 g/cm3, which is the value at room temperature, to be c11D=8.31×1011 dyn/cm2, c12=2.88×1011 dyn/cm2, c44D=6.63×1011 dyn/cm2.