Finding a Piezo Resonance

The resonant frequency of the piezo you are using is important to know in some situations. For example, if a cavity mirror has a piezo it is important to know the piezo's resonant frequency for locking purposes. Tyler green discusses this on page 34 in his thesis.

As an example, you might have a setup like the one shown below. Both the laser and the cavity have piezos on them. Each piezo will need to be hooked up to a function generator.

Figure 2. Cavity resonance peaks

Figure 3. Piezo oscillating with small sinusoidal voltage

Figure 4. Piezo is close to resonance, the peaks begin to oscillate with larger amplitude

• Ramp the laser piezo and align the cavity so that you can see transmission peaks with the photo diode (figure 2).