Micro-Fresnel lenses

Fig. 18. Schematics of the fabrication of micro fresnel lenses by two-wave mixing, [35]...

T. Fujita, FI. Nishihara, and J. Koyama, "Micro Fresnel lenses fabricated by electron-beam lithography," Electronics and Communications in Japan, vol. 64-C, pp. 104-110,1981. 

Purely diffractive micro Fresnel lenses can also be obtained holographically, by the interference of a convergent or divergent laser beam with a planar wave in a Mach-Zehnder interferometer, as shown in Figure 16.13. Figure 16.14 shows the structure of a lens produced by this technique from a photosensitive nanocomposite material. 

Figure16.12 Fresnel lens (a) Principleofcreatinga refractive Fresnel lens by segmenting a normal plano-convex lens, (b) Large-area AFM image of the center of an embossed micro Fresnel lens (side length is 150 pm).

Figure 16.13 Setup for holographic writing of a micro Fresnel lens. A linearly polarized collimated beam from an Ar + -Laser (wavelength 351 nm) is divided by a beam splitter into two beams the object beam illuminates the test object through a lens L2. The reference beam recombines with the object...

Figure 16.14 Holographic micro Fresnel lens as seen by (a) optical microscopy (b) and scanning electron microscopy (Reproduced with permission from [47]. Copyright (2007) SPIE.)...

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