$sound wave diffraction$

$sound wave diffraction$

SOUND WAVE DIFFRACTION FULL

Technically, sound is defined as a mechanical disturbance traveling through an elastic medium - a material that tends to return to its original condition after being deformed. Wavelength is the distance between any point on a wave and the corresponding point on the next wave. Ultrasound is sound with frequencies above the range of human hearing-that is, above 20,000 hertz. Sound quality distinguishes between notes of the same frequency and intensity that are produced by different musical instruments. Sound quality, also called timbre, is a characteristic of musical sounds. Sound medium is a substance in which sound waves travel. Resonance frequency is the frequency at which an object would vibrate naturally if disturbed. Rarefaction is a region in a sound wave in which the density of the sound medium is less than normal. Pitch is the degree of highness or lowness of a sound as we hear it. Noise is a sound that is unpleasant, annoying, and distracting. Loudness refers to how strong a sound seems when we hear it. Intensity of a sound is a measure of the power of its waves. One hertz equals one cycle (vibration, or sound wave) per second. Hertz is the unit used to measure frequency of sound waves. A 3,000-hertz tone of 0 dB is the softest sound that a normal human ear can hear.įrequency of a sound is the number of sound waves that pass a given point each second. It can be used in nondestructive testing, structural health monitoring and biomedical applications, where optically generated and optical measurements of ultrasound gives a non-contact method of imaging.Acoustics is the science of sound and of its effects on people.Ĭondensation is a region in a sound wave in which the sound medium is denser than normal.ĭecibel (dB) is the unit used to measure the intensity of a sound. Technical progress in both crystal growth and high frequency piezoelectric transducers has brought valuable benefits to acousto-optic components' improvements.Īlong with the current applications, acousto-optics presents interesting possible application. This is due to the increasing availability and performance of lasers, which have made the acousto-optic effect easier to observe and measure. However, the growing principal area of interest is in acousto-optical devices for the deflection, modulation, signal processing and frequency shifting of light beams. The acousto-optic effect is extensively used in the measurement and study of ultrasonic waves.

$sound wave diffraction$

These variations in the refractive index, due to the pressure fluctuations, may be detected optically by refraction, diffraction, and interference effects reflection may also be used. Sound waves produce a refractive index grating in the material, and it is this grating that is 'seen' by the light wave. In general, acousto-optic effects are based on the change of the refractive index of a medium due to the presence of sound waves in that medium. This model was developed by Phariseau (1956) for diffraction including only one diffraction order. Raman and Nath (1937) have designed a general ideal model of interaction taking into account several orders. The particular case of diffraction on the first order, under a certain angle of incidence, (also predicted by Brillouin), has been observed by Rytow in 1935. This was then confirmed with experimentation in 1932 by Debye and Sears, and also by Lucas and Biquard. In contrast, the acousto-optic effect has had a relatively short history, beginning with Brillouin predicting the diffraction of light by an acoustic wave, being propagated in a medium of interaction, in 1922. As with optics, acoustics has a history of similar duration, again starting with the ancient Greeks.

$sound wave diffraction$

SOUND WAVE DIFFRACTION FULL

Optics has had a very long and full history, from ancient Greece, through the renaissance and modern times. Acousto-optics is a branch of physics that studies the interactions between sound waves and light waves, especially the diffraction of laser light by ultrasound (or sound in general) through an ultrasonic grating.Ī diffraction image showing the acousto-optic effect.

$sound wave diffraction$

Sound wave diffraction