Acquisition of PSV-500 Compact Scanning Laser Vibrometer
Abstract
We propose to acquire a PSV-500 Compact Scanning Laser Vibrometer, Polytec Inc., to augment current and develop new research capabilities in support of the ONR research project N00014- 17-1-2521 “Thermoacoustic Carbon Nanotube Sound Projectors with Enhanced Efficiency and Broad-Band Acoustic Spectra”. This device is capable of remote measurement of velocity and displacement of fluid particles, visualize vibrational modes of thin membranes, and monitor a sound pressure field profile (using acousto-optic effect) in the frequency range up to 25 MHz. The system consists of a portable scanning laser head with high precision scanner, High-Definition (HD) video camera, time domain data acquisition and animation electronic board, and a computer with monitor. The device uses laser Doppler vibrometry, yielding the highest displacement (< 2 nm) and velocity (0.01 ?m/s) resolutions among existing technologies. The laser beam as a sensor does not influence the sample, making it non-invasive and therefore enabling measurements to be carried out on extremely small and lightweight structures. This ability is especially important for development of wideband thermoacoustic sound projectors and new sound pressure field detectors based on nanostructured materials like carbon nanotubes and graphene. The laser vibrometer will enable us to enhance research activities in the field of thermoacoustic sound generation via developing new techniques for monitoring the sound field profile in air and underwater, in infrasound (< 20 Hz) and far ultrasound (> 200 kHz) regions. It will expand our research capabilities to new fields such as acoustic phonon crystals and metamaterials for wide range of applications, particularly, for sound amplifiers and accelerators based on transparent carbon nanotube sheets. Using the non-invasive scanning laser beam, we will study the vibrational modes of thin (<100 ?m) membranes of encapsulated thermoacoustic projectors at variable pressures of filled inert gases and external water. The current existing microphones (< 140 kHz) and hydrophones (< 200 kHz) do not satisfy the desired frequency range. They are large, bulk, and substantially disturb the pressure field. To cover these frequencies we will use the vibrations of reference thin film graphene (< 1 ?m) placed in a sound propagation fluid. Using laser vibrometer to control the interaction of freestanding nanostructures with surrounding fluid molecules, we will study the out-of-plane vibrations of freestanding carbon nanotubes and graphene sheets at different thermal and mechanical excitations. This information, combined with the behavior of flexural and other out-of-plane modes, obtained from Brillouin and Raman scattering experiments, will shed light on the mechanism of interaction of fluid molecules with nanostructures and indicate on alternative materials with optimal heat exchange coefficients. The system proposed to acquire will be very useful for research and education in the field of artificial muscles and actuations, where the monitoring of nanoscale deformation of electrochemically or thermally actuated nanostructures will give a new insight on basic mechanisms. The projects outlined in this proposal require the ability to use a non-invasive technique to determine the displacements of molecules or rigid membranes with at least nanometer resolution, the ability to characterize the evolution of surface deformation under different environments, and the ability to visualize the three-dimensional (3D) microstructures as a function of excitation fields and time. The proposed PSV-500 Compact Scanning Laser Vibrometer is a universal and flexible system that can address the needs in these research activities.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 08, 2020
- Source ID
- N000141912685
Entities
People
- Ali Aliev
Organizations
- Office of Naval Research
- United States Navy
- University of Texas at Dallas