Radiation induced sound
Abstract
Radiation induced sound experiments were conducted with up to four 10.6-micron CO2 laser pulses. These experiments were conducted to demonstrate the ability to control the acoustic energy spectral density by varying the time between laser pulses. The acoustic signatures were Fourier analyzed to obtain the energy spectral density. The results show that if the pulses are evenly spaced and uniform in amplitude, the ratio of the width of a peak in the spectrum to the fundamental frequency scales approximately as the inverse of the number of pulses. Alternatively, the results show that this scaling does not hold if the pulses are not evenly spaced or not uniform in amplitude. Theoretical modeling was performed to obtain scaling laws relating laser parameters to acoustic parameters of the generated signatures. Predictions were also made of the change in amplitude and shape of the broadband signals due to frequency-dependent absorption as a function of propagation distance.
- Publication:
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American Institute of Aeronautics and Astronautics
- Pub Date:
- October 1978
- Bibcode:
- 1978fdhp.confR....N
- Keywords:
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- Acousto-Optics;
- Carbon Dioxide Lasers;
- Infrared Lasers;
- Pulsed Lasers;
- Amplitudes;
- Broadband;
- Electromagnetic Absorption;
- Energy Spectra;
- Far Fields;
- Fourier Analysis;
- Scaling Laws;
- Signature Analysis;
- Lasers and Masers