Investigations of the three-dimensional intensity distribution near the focus are extended here to systems with Fresnel numbers N < 0.5. Isophotes (contours of equal intensity) are presented that demonstrate the structure of the field deep within the region of Fresnel diffraction.
© 1987 Optical Society of America
Yajun Li, "Three-dimensional intensity distribution in low-Fresnel-number focusing systems," J. Opt. Soc. Am. A 4, 1349-1353 (1987)