Glossary - alphabet order - "W"

Wave front

The same phase plane of light waves having the same peak and valley positions (same phase) when light rays are propagated through air or a substance.

Wave front aberration

A deviation from the ideal wavefront (from a straight line), generated after light has passed through an optical component such as a waveplate or prism, or has been reflected by a mirror. The amount of an aberration is expressed as wavelength units. This amount for the entire surface of a component indicates the plate's parallelism, surface roughness or distortion, etc.

Wavefront aberration for transmission (Transmitted wavefront aberration)

Wavefront aberration in a transmission path. This indicates distortion or surface roughness of the incident/exit surface in a prism.

Wavefront aberration for reflection

Wavefront aberration in a reflection path. This indicates distortion or surface roughness of the incident/exit surface, as well as distortion or surface roughness of applied surfaces (such as the coated surface of a triangular prism) in a prism.


It indicates a unit of length for waves. The wavelength is measured as the distance between consecutive peaks or valleys in a wave.

Visible color of light is changed depending on the light's wavelength.
Infra red light is used for remote control units and other devices due to its advantages in terms of cost, response speed, etc.


It is made of a birefringent crystal or anisotropic material, giving an optical path difference (a phase difference) to incident light. The optical path difference is yielded among the components of incident light after outputting from the waveplate. The optical path difference is caused by a different propagation velocity (refractivity) between one component (a parallel component) oscillating within a specific surface and the other component (a perpendicular component) oscillating perpendicularly to the surface. This specific surface is defined as a plane formed with the optical axis of the waveplate and the incident light beam.

White plate glass

A typical example is Schott B270.

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