I have recently completed a BTech(Hons) degree, majoring in medical physics and thermal imaging technology, at the University of Auckland. Currently I am working towards a PhD in Physics in the Physical Acoustic Lab. My research is centred around development of optical devices which can be used to measure acoustic waves.
- Heterodyne Interferometry
- Fiber based strain meter
- High Pressure rock physics
Laser Doppler Vibrometers (LDVs) are used in research and industry to measure acoustic waves in media. LDVs measure the velocity of a sample by measuring the Doppler shift of the reflected light. Researchers in the PAL are typically interested in high frequency (ultrasonic) acoustic waves. Due to the high frequency, even small sample displacements result in large particle velocities, and thus LDVs provide an excellent method of noncontacting detection. Laser based devices also have several advantages over contacting piezoelectric transducers such as ease of scanning, limited coupling inconsistencies and much greater traversal resolution (100s of μm).
At the centre of data acquisition in the PAL is a commercial LDV; Polytec’s OFV-505 sensor head coupled with the OFV-5000 vibrometer controller. However, with commercial systems come proprietary limitations, such as signal delays and potentially unknown frequency filtering. LDVs also come at a significant cost to the PAL. Because of this, I developed the Open Source Laser Doppler Vibrometer (OSLDV).
The details of the inner workings of the OSLDV, including the construction of the interferometer and demodulation electronics, can be found in our European Journal of Physics publication: Heterodyne interferometry for the detection of elastic waves: a tutorial and open-hardware project.
PhD Draft plan: