Gradient index

Vacha M, Yokoyama N, Tokizaki T, Furuki M and Tani T 1999 Laser scanning microscope for low temperature single molecule and microscale spectroscopy based on gradient index optics Rev. Sc/. Instrum. 70 2041-5... 

Figure 12.8. Transmission characteristics of some commonly used optical fibers, (a) glass fiber (b) gradient-index fiber (c) plastic-clad silica fiber (d) plastic fiber. (Reproduced with permission from the Ealing Corporation.)...

WMM represents a stable mode solving technique, where, similar to TMM, continuous geometrical profiles and gradient index media require a staircase-approximation. Accuracy is affected if boundaries are too close to the guiding structure, or if the number of ID modes is too low, which both is easy to check. So, WMM is a stable and accurate mode-solving technique. It... 

Cox WR, Guan C. (2001) inkjet printing of gradient-index microlenses, US patent application 2001048968. 

We mentioned above three types of optical fibers step index single mode, step index multimode, and gradient index multimode. The last two types can carry more light that the step index single mode fiber. Lightness is a very important feature. Among the important features for such a system are the following (Oare, 1995) ... 

FIGURE 4-1 Refractivity and core diameter ranges for three types of optic fibers, (a) Multi-mode step-index optic fiber, (b) Multi-mode gradient-index optic fiber, (c) Single model step-index optic fiber. 

In this chapter, recent progress in several key areas is reviewed. These areas are catagorized by material classification rather than by end-use application (1) bulk silica optics (2) optically active doped silica glasses (3) gel-polymer composites (4) organically modified silicates (ormosils) and (5) gradient-index glasses. These represent the five most significant developments in the area of bulk optical materials by the sol-gel process to date. 

Yamane, M., Kawazoe, H., Yasumori, A., and Takahashi, T., Gradient-index glass rods of PbO-KzO- B2O3 -Si02 system prepared by the sol-gel process, J. Non-Cryst. Solids, 100, 506-510 (1988). 

Yamane, M., Gradient-index materials by the sol-gel process, in Ultrastructure Processing of Advanced Materials (D. R. Uhlmann and D. R. Ulrich, eds.), Wiley and Sons, New York, 1992, pp. 509-517. 

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]. 

Optical fibres are convenient for sending light from one place to another. Once the light is coupled into one end of a fibre it arrives at the other, regardless of how the fibre is bent or moved. Optical fibres come in three versions - multimode fibres, gradient-index fibres, and single-mode fibres (Fig. 7.21). 

Fig. 7.21 Light propagation in a multimode fibre, a gradient-index fibre, and a single-mode fibre...

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)... 

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