Lenses gradient-index

M.J. Levene, D.A. Dombeck, R.M. Williams, J. Skoch, G.A. Hickey, K.A. Kasischke, R.P. Molloy, M. Ingelsson, E.A. Stem, J. Klucken, B.J. Bacskai, W.R. Zipfel, B.T. Hyman, W.W.W. Webb, In vivo multiphoton microscopy of deep tissue with gradient index lenses, Proc. SPIE 5323, 291-296 (2004)... 

In ordinary batch copolymerization there is usually a considerable drift in monomer composition because of different reactivities of the two monomers (based on the values of the reactivity ratios). This leads to a copolymer with a broad chemical composition distribution (CCD). In many cases (depending on the specific final product application) a composition drift as low as 3-5% cannot be tolerated, for example, copolymers for optical applications on the other hand, during production of GRIN (gradient index) lenses, a controlled traj ectory of copolymer composition is required. This is partly circumvented in semibatch operation where the composition drift can be minimized (i.e., copolymer composition can be kept constant ) by feeding a mixture of the monomers to the reactor with the same rate by which each of them is consumed in the reactor. 

Microoptics, which consists of microlenses such as gradient-index lenses or tiny spherical lenses... 

J. Knittel, L. Schnieder, G. Buess, B. Messerschmidt, and T. Possner, "Endoscope-compatible confocal microscope using a gradient index-lens system," Optics Communications, vol. 188, pp. 267-273, Feb 2001. 

Koike Y.,Hidaki H., Ohtsuka Y. / Plastic axial gradient-index lens 11 Appl. Opt. 1985, vol. 24, No 24, pp. 4321-4325. 

Fig. 2.4 Some spherical and aspheric discrete microlenses for optical concentrators in MWIR and LWIR range that may be fabricated by microsystem technologies, a calotte b hemisphere c hyperhemisphere d ball lens e truncated sphere f bulb g hemi-cylinder h cylinder i curvilinear cone j concave concentrator k gradient-index lens (GRIN) I complex two-element lens (sphere/GRIN). The grid corresponds to the homogeneity of refractive index, i.e., describes its gradient...

The transparency and refractive power of the lenses of our eyes depend on a smooth gradient of refractive index for visible light. This is achieved partly by a regular packing arrangement of the cells in the lens and partly by a smoothly changing concentration gradient of lens-specific proteins, the crystallins. 

Many modifications of the optical system are possible. For example, the scan mirrors can be placed between LI and L2 LI can be a negative lens, or L2 and L3 can be combined into one lens. L3 can be replaced with an endoscope. Moreover, the focus of L3 can be scanned over the input plane of a gradient-index (GRIN) lens (see Fig. 7.9, page 273). The GRIN lens can be used as a miniature endoscope [320]. 

Tunable Liquid Gradient Refractive Index Lens... 

Linsky R. / Gradient-index meniscus lens free of spherical aberration. II J. Opt. 2000, 2,... 

Fig. 2.14 The scheme of the cylindrical lens method for diffusion coefficient measurement (1) the source with the horizontal slit (2) the condenser supplying a handle of parallel beams (3) the cuvette with a refraction index gradient where the beams are deflected (4) the objective lens focusing the parallel beams to a single point (5) the optical member with an oblique slit and a cylindrical lens (6) the photosensitive material...

Refraction of radiation can also occur in fluidic regions with refractive index gradients because optical artefacts analogous to fluidic lenses are established. Regardless of the process (reflection or refraction) and the optical artefact (mirror or lens) involved, the deflection of radiation inside a fluidic environment can result in external distortions, characterised by the Schlieren effect. 

Another GRIN system is the binary titania-silicate system of Konishi and coworkers [62,63]. Small 2 mm diameter lens of low A-n have been produced with good index profiles [62, 63]. The low solubility of titanium dioxide in silica limits the maximum refractive index gradient in this binary system. 

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