Q-Switching Frequency for Acousto-Optic Modulator & 980nm Laser

[whatisreality]

Homework Statement

An acousto-optic modulator is used to Q-switch a laser with $\lambda = 980$nm. The angle of deflection is $\theta = 0.1$ degrees, the speed of sound in quartz is 3700m/s and it has refractive index of 1.5. What is the maximum Q switch rate?
I'm not exactly sure what I'm being asked to do - I think by switch rate it might mean the frequency of pulses? If that's the case and I calculate the wavelength of the sound in quartz, would the pulse separation be $t = \frac{2n\lambda}{c}$? Usually the $\lambda$ would be the cavity length $L$, but in this case are they equal?

Homework Equations

The Attempt at a Solution

 

[NateD]

I think the answer might be $f = \frac{3700\cdot 10^3}{2 \cdot 1.5 \cdot 0.01 \cdot 9.8 \cdot 10^{-6}} = 18.9 \cdot 10^6 \text{Hz}$