ABSTRACT
To evaluate the consistency of PZTs, a novel method based on folded-cavity He-Ne laser has been proposed and demonstrated. In this method, the laser’s intensity and frequency are modulated by the voltages put on the PZTs beside the reflecting mirrors. Because of the nonlinear responses and different piezoelectric coefficients of PZTs, the cavity length could not stay unchanged under the same driving voltages, neither could the laser intensity and frequency. Thus, the inconsistency of PZTs to voltages can be evaluated through these parameters of the laser. A nearly double difference on piezoelectric coefficients between the two used PZTs are detected in both approaches, intensity modulation and frequency-beat system. The first approach provides a quick response method to evaluate the consistency of PZTs and the second approach provides a high precision method, whose resolution can reach 0.026 nm/V. And the second approach shows two orders of magnitude higher resolution than the first one.
