Accession Number : AD0765482

Title :   Laser Beam Divergence and Far Field Measurements.

Descriptive Note : Technical research rept.,

Corporate Author : FRANKFORD ARSENAL PHILADELPHIA PA

Personal Author(s) : Holst,Gerald C.

Report Date : MAY 1973

Pagination or Media Count : 29

Abstract : Accurate determination of beam divergence and far field intensity distribution require careful determination that the far field is being examined. Although the far field exists at a sufficiently large distance from the laser, it is easier to perform measurements in the focal plane of a lens which is equivalent to an infinite distance. The beam divergence is specified as that angle which contains a certain percentage of the total power in the far field. Since this is a plane angle, confusion arises between the intensity distribution (w/sq. cm) and the power distribution (watts). Several methods are available for determining the divergence from the far field pattern. These methods are experimentally verified with a He-Ne laser. Construction of a unique portable two lens far field camera is discussed. (Author)

Descriptors :   (*COHERENT RADIATION, SCATTERING), GAS LASERS, ATMOSPHERIC MOTION, LIGHT TRANSMISSION, MEASUREMENT

Subject Categories : Lasers and Masers
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE