Prisms on a surface splitting light

Gaussian beam

Gaussian beam

A beam of electromagnetic radiation whose wave front is approximately spherical at any point along the beam and whose transverse field intensity over any wave front is a Gaussian function of the distance from the axis of the beam. A Gaussian function is a mathematical function like the one below that expresses the circular cross section amplitude:

E ( r ) = E ( 0 ) e ( r / w ) 2 MathType@MTEF@5@5@+=feaagCart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqipu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyraiaacIcacaWGYbGaaiykaiabg2da9iaadweacaGGOaGaaGimaiaacMcacaWGLbWaaWbaaSqabeaadaqadaqaaiaadkhacaGGVaGaam4DaaGaayjkaiaawMcaamaaCaaameqabaGaaGOmaaaaaaaaaa@4301@ ,

where E(r) is the amplitude of the electric field at a radial distance r from the center of the beam, E(0) is the amplitude at the center of the beam (usually maximum amplitude), and w is the radial distance at which the amplitude of the electric field is 1/e ≈ 1/2.71828 of its value on the axis. The variable w is usually called the beam width.

To learn more, click on the link to the Lasers in Everyday Life pamphlet.