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Acousto-optic effectThe acousto-optic effect describes the interaction between sound and light. The understanding of the physical principles governing this phenomenon can be used as an alternative to conventional acoustic measurement methods.
Below you can find a very brief description of our first measurement results, where we examined the possibility of using a laser Doppler vibrometer (LDV) to measure the acousto-optic effect in air and within the audible frequency range. You can find more information in my list of publications. Measurement setupThe measurements were carried out in the big anechoic room of the acoustics group at DTU. The experimental setup consisted of an LDV that integrated the spherical sound field radiated by a loudspeaker as illustrated in the picture below. The rod hanging from the ceiling sustained a microphone that was aligned with the loudspeaker.
First experimental resultsThe picture below shows the sound pressure level measured with the microphone (red curve) and with the LDV (blue curve). As you can see, there is a fairly good agreement above 2 kHz. The results obtained with the LDV below 2 kHz are biased by the mechanical vibrations of the experimental setup.
Audio samplesTo further illustrate the possibility of measuring sound using the acousto-optic effect, some recordings with music were also performed. Below you can find a sample of music recorded with the LDV and with the microphone. Note that both recordings have been high-pass filtered in order to remove the influence of the mechanical vibrations contaminating the measurements of the LDV below 2 kHz.
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