Abstract
Lenses for focusing laser beams can be designed by use of conventional methods, but since laser beams are monochromatic, and have angular divergences that are limited by diffraction, the requirements for an optimized design are different than those for an ordinary lens. In particular, in a weakly focused beam, the axial locations of the paraxial focus and the gaussian beam waist do not coincide. Although the focus shift is small for a beam of low f number, when the f number is as large as f/1000 (a common value in certain types of laser systems), the shift may be comparable to the focal length. Such a shift should be taken into account in an optimized focusing system, although the extremely large depth of focus obtained with a beam of such large f number makes the resultant image blur rather small.
© 1974 Optical Society of America
Full Article | PDF ArticleMore Like This
Gabriel Otis
J. Opt. Soc. Am. 64(11) 1545-1550 (1974)
Fred Mandelkorn
J. Opt. Soc. Am. 64(3) 310-313 (1974)
E. W. Marchand and D. J. Janeczko
J. Opt. Soc. Am. 64(6) 846-849 (1974)