We describe a technique for measuring the three-dimensional (3D) intensity distribution of a paraxial focus, based on scanning a CCD image sensor along the optical axis and on subsequently analyzing the data. We demonstrate the possibility of measuring high-resolution 3D intensity maps of the focal field, down to intensities of more than 5 orders of magnitude below that in the focal point, and show the excellent agreement with scalar diffraction theory. Further applications of the technique are indicated.
© 1997 Optical Society of America
Original Manuscript: February 12, 1997
Revised Manuscript: June 20, 1997
Published: November 1, 1997
G. P. Karman, A. van Duijl, M. W. Beijersbergen, and J. P. Woerdman, "Measurement of the three-dimensional intensity distribution in the neighborhood of a paraxial focus," Appl. Opt. 36, 8091-8095 (1997)