Improvement in Laser Pulse Methods for Piezoelectric Device Analysis Using Laser Speckle Interferences

SummaryPiezoelectric oscillators, which are a type of quartz crystal device that converts pressure and electric power, are used in various electronic devices. Visualizing of the vibration mode of the oscillators is extremely important in design, and one method for doing so is the laser speckle method, in which the surface of the oscillator is irradiated with a laser and the state of vibration is observed from the speckle. In this paper, we focus on the laser speckle pulse method, which has much higher sensitivity than the conventional method, and we obtain basic data on the method, such as the optimum phase angle of the laser pulse with respect to the drive voltage of the oscillator. Since the frequency range of the proposed system is limited only by that of the RF-generator (7GHz) that excites the device under test, the system can be applied to ultra-high frequency devices such as MEMS devices operating in the GHz range.