Apparatus for measuring a beam width D.sub..sigma.x along a transverse direction of a laser beam and method thereof
US5587786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 1995 |
| Grant date | Dec 24, 1996 |
| Priority date | — |
| Expiry date | Feb 23, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J1/4257
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to an apparatus and a method upon which the apparatus is based for direct optical measurement of first and second moments (variance) of two-dimensional continuous-wave optical beam irradiance distributions. The apparatus and method are based on an optical filter having a spatially-varying transmittance or reflectance profile described by a one-dimensional truncated parabolic function. The light power transmitted through or reflected by the optical filter is measured by a photodetector as the optical filter travels horizontally across the beam irradiance profile. The variance is obtained from the ratio of the peak signal given by the photodetector normalized to the signal corresponding to the total optical power of the unobstructed optical beam. The first moment in a fixed reference frame is given by the horizontal position of the region of peak transmittance/reflectance of the filter when the maximum signal is measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.