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A geometrical arrangement used in deriving the Kirchhoff's diffraction formula. The area designated by A 1 is the aperture (opening), the areas marked by A 2 are opaque areas, and A 3 is the hemisphere as a part of the closed integral surface (consisted of the areas A 1, A 2, and A 3) for the Kirchhoff's integral theorem.
The Kirchhoff–Helmholtz integral combines the Helmholtz equation with the Kirchhoff integral theorem [1] to produce a method applicable to acoustics, [2] seismology [3] and other disciplines involving wave propagation. It states that the sound pressure is completely determined within a volume free of sources, if sound pressure and velocity ...
In physics, the acoustic wave equation is a second-order partial differential equation that governs the propagation of acoustic waves through a material medium resp. a standing wavefield. The equation describes the evolution of acoustic pressure p or particle velocity u as a function of position x and time t. A simplified (scalar) form of the ...
Modeling the diffraction of a CW (continuous wave), monochromatic (single frequency) field involves the following steps: Sampling the complex (real and imaginary) components of a pressure field over a grid of points lying in a cross-sectional plane within the field.
Λ is the wavelength of the sound wave, λ is that of the light wave, and n is the refractive index of the crystal in the AOD (which should be omitted. This is a mistake). This is a mistake). The +1 order has a positive frequency shift compared to the incident light; The 0th order has the same frequency as the incident light.
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. A diffraction image showing the acousto-optic effect.
It is possible to apply the transfer-matrix method to sound waves. Instead of the electric field E and its derivative H , the displacement u and the stress σ = C d u / d z {\displaystyle \sigma =Cdu/dz} , where C {\displaystyle C} is the p-wave modulus , should be used.
Because diffraction is the result of addition of all waves (of given wavelength) along all unobstructed paths, the usual procedure is to consider the contribution of an infinitesimally small neighborhood around a certain path (this contribution is usually called a wavelet) and then integrate over all paths (= add all wavelets) from the source to the detector (or given point on a screen).