The introduction of spherical aberration in a lens design can be used to extend the depth of field while preserving resolution up to half the maximum diffraction-limited spatial frequency. Two low-power microscope objectives are shown that achieve an extension of ±0.88 λ in terms of wavefront error, which is shown to be comparable to alternative techniques but without the use of special phase elements. The lens performance is azimuth-independent and achromatic over the visible range.
© 2008 Optical Society of AmericaFull Article | PDF Article
David G. A. Jackson, Min Gu, and Colin J. R. Sheppard
J. Opt. Soc. Am. A 11(6) 1758-1767 (1994)
Alan R. FitzGerrell, Edward R. Dowski, and W. Thomas Cathey
Appl. Opt. 36(23) 5796-5804 (1997)
H. Bartelt, J. Ojeda-Castañeda, and Enrique E. Sicre
Appl. Opt. 23(16) 2693-2696 (1984)