THE CORRELATION OF APPLIED VOLTAGE ON PIEZOELECTRIC TRANSDUCERS (PZT'S) TO DISPLACEMENT. Chris Wottawa, Harold Metcalf, John Noe, Laser Teaching Center, Department of Physics and Astronomy, SUNY at Stony Brook.
Plumbum Zirconium Titanate (PZT) is a ceramic material with the
unique ability to transform an applied voltage into a small (typically
nanometer) mechanical displacement, or vice versa. This property, the
Piezoelectric Effect, which was discovered by Pierre and Jacques Curie
in 1880, now has applications in almost all fields of science and
technology. Because of this effect, these special ceramic materials
have become known as piezoelectric translators or transducers (also
The purpose of this project is to measure the minute displacements of
various PZT disks as a function of applied voltage. The PZT samples
(PIC-155, PIC 151, etc) were obtained from the PhysikInstrument
Company in Auburn, Mass. The tiny displacements are measured using
light waves as a ruler with the help of a Michelson Interferometer.
Light from a He-Ne laser (wavelength = 632.8 nm) is projected with the
help of two adjustable mirrors through a diverging lens and then into
the interferometer. The interferometer consists of two mirrors and a
beam splitter, which, when aligned perfectly, forces laser beams to
travel over two perpendicular paths and interfere as they
recombine. This results in circular fringes (alternating rings of
light and dark), caused by the alternating constructive and
destructive interference. The radius of the fringes is directly
related to the separation of the mirrors (the difference in path
length of the two beams).
Up to now, the Michelson interferometer has been assembled and
successfully aligned to produce good circular fringes. It was found
that the instrument is extremely sensitive to vibrations transmitted
through the optical table and surrounding air. We are now trying
various methods to reduce these vibrations. After stable fringes are
achieved a PZT will be mounted to one of the mirrors. Voltages
applied to the transducer will cause displacements which will be
measured by the shifts in the fringes.
This project was supported by a Symbol Technologies Fellowship and grants from ARO and ONR.