Achromatic hybrid refractive-diffractive lens with extended depth of focus.

A method for designing achromatic hybrid refractive-diffractive elements that can produce beams with long focal depths while they preserve the entire aperture for capture of light and high transverse resolution is presented. Its working principle is based on the combination of a diffractive optical element that generates a long range of pseudonondiffractive rays and a refractive lens of opposite dispersion to form an achromatic hybrid lens. A hybrid lens with a fast f-number (f/1) that works in the entire visible wave band (400-700 nm) was designed and fabricated. Simulation results demonstrate a factor-of-10 improvement in depth of focus compared with that of a conventional f/1 lens, with matching 1-microm lateral resolution. Experimental results confirm the effectiveness of the proposed method through demonstration of an achromatic hybrid lens with better than a factor-of-7 improvement in depth of focus and 1-microm transverse resolution.

[1]  Bernard C. Kress.  Digital diffractive optics , 2000 .

[2]  J R Fienup,et al.  Phase-retrieval algorithms for a complicated optical system. , 1993, Applied optics.

[3]  W T Cathey,et al.  Control of chromatic focal shift through wave-front coding. , 1998, Applied optics.

[4]  Nir Davidson,et al.  Analytic design of hybrid diffractive-refractive achromats. , 1993, Applied optics.

[5]  W. Cathey,et al.  Extended depth of field through wave-front coding. , 1995, Applied optics.

[6]  A A Friesem,et al.  Holographic axilens: high resolution and long focal depth. , 1991, Optics letters.

[7]  Guo-Zhen Yang,et al.  Generation of pseudo-nondiffracting beams with use of diffractive phase elements designed by the conjugate-gradient method , 1998 .

[8]  Yang Guozhen,et al.  ON THE AMPLITUDE-PHASE RETRIEVAL PROBLEM IN OPTICAL SYSTEMS , 2005 .

[9]  Z. Jaroszewicz,et al.  Nonparaxial design of generalized axicons. , 1992, Applied optics.

[10]  G. Häusler,et al.  A method to increase the depth of focus by two step image processing , 1972 .

[11]  P. Clark,et al.  Modeling diffraction efficiency effects when designing hybrid diffractive lens systems. , 1992, Applied optics.

[12]  J. Mcleod,et al.  Axicons and Their Uses , 1960 .

[13]  M R Wang,et al.  Laser direct-write gray-level mask and one-step etching for diffractive microlens fabrication. , 1998, Applied optics.

[14]  Réal Tremblay,et al.  Focal depth of a transmitting axicon , 1973 .

[15]  R. Gerchberg.  A practical algorithm for the determination of phase from image and diffraction plane pictures , 1972 .

[16]  Fuxi Gan,et al.  Phase-shifting apodizers for increasing focal depth. , 2002, Applied optics.

[17]  N Yoshikawa,et al.  Phase optimization of a kinoform by simulated annealing. , 1994, Applied optics.

[18]  Ari T. Friberg,et al.  Stationary-phase analysis of generalized axicons , 1996 .

[19]  G. M. Morris,et al.  Wavefront quality of optimized diffractive lenses , 1997 .

[20]  M. Feldman,et al.  Iterative discrete on-axis encoding of radially symmetric computer-generated holograms , 1993 .

[21]  Changyuan Yu,et al.  Efficient pseudo-nondiffracting beam shaping using a quasicontinuous-phase diffractive element , 2001 .

[22]  B Y Gu,et al.  Implementation of pseudo-nondiffracting beams by use of diffractive phase elements. , 1998, Applied optics.

[23]  J Turunen,et al.  Realization of general nondiffracting beams with computer-generated holograms. , 1989, Journal of the Optical Society of America. A, Optics and image science.

[24]  Ben-Yuan Gu,et al.  Generation of nondiffracting beams by diffractive phase elements , 1998 .