Polarizing effect with doubly rotated α-quartz plates vibrating in thickness

The magnitude of the polarizing effect is calculated for the three thickness modes in the entire primitive region of α-quartz. For each mode the maximum values of the relative frequency change (1/f) (Δf/ΔE)) exceeds 10^-11V^-1m. In resonators operated in series resonance and driven at 0.1 mW level, the ac electric fields easily reach 10³ Vm^-1 Similar de electric fields can cause frequency shifts as large as several parts in 10⁸.