Wavenumber
2024-2-16
Definition:
Phase delay per unit length, or this value divided by 2π.
There are different definitions of wavenumber. The physical definition is:
where λ is the wavelength in the medium (not the vacuum wavelength). The wave number is the size of the wave vector and the phase delay per unit length during the propagation of a plane wave.
Another definition:
The unit is cm-1, which is commonly used in spectroscopy. To avoid confusion, the first quantity can be called the angular wave number (similar to the angular frequency), but this is less common.
The wave number of a light wave in a medium is equal to the vacuum wave number times the refractive index.
The wave number is related to the phase change per unit length of a plane wave propagating in an isotropic medium. The phase change per unit length of the focused beam requires some corrections based on the plane wave. For example, the correction term for a Gaussian beam is the Goui phase shift. For guided waves propagating in a waveguide, the imaginary part of the propagation constant γ (also called β) is related to the phase change per unit length.
Phase delay per unit length, or this value divided by 2π.
There are different definitions of wavenumber. The physical definition is:
where λ is the wavelength in the medium (not the vacuum wavelength). The wave number is the size of the wave vector and the phase delay per unit length during the propagation of a plane wave.
Another definition:
The unit is cm-1, which is commonly used in spectroscopy. To avoid confusion, the first quantity can be called the angular wave number (similar to the angular frequency), but this is less common.
The wave number of a light wave in a medium is equal to the vacuum wave number times the refractive index.
The wave number is related to the phase change per unit length of a plane wave propagating in an isotropic medium. The phase change per unit length of the focused beam requires some corrections based on the plane wave. For example, the correction term for a Gaussian beam is the Goui phase shift. For guided waves propagating in a waveguide, the imaginary part of the propagation constant γ (also called β) is related to the phase change per unit length.
