Perfect lens

Figure 1. Ray optical description of lens aberrations, (a) Perfect lens imaging a point P in the object plane onto a sharp point in the image plane, (b) Lens affected by spherical aberration, (c) Lens underfocused by a distance Z. (d) Lens overfocused by a distance Z. Spherical aberration and defocusing cause a blurring of the point P in the image plane.

The optical treatment in Chapter 1 is concerned with the nature of the image of a simple two-dimensional grid formed by a perfect lens, in focus, using monochromatic light. However, to understand the nature of the lattice image formed in the electron microscope, we must take into account the thickness and the orientation of the three-dimensional crystal, the defect of focus and the aberrations of the objective lens (see Chapter 2), and the beam convergence, because all these factors influence the relative phases of the diffracted beams that are permitted to pass through the objective aperture. 

J.B. Pendry, Negative refraction makes a perfect lens. Phys. Rev. Lett. 85(18), 3966-3969 (2000)... 

For both one- and two-photon processes, the irra-diance is greatest at the beam waist. Consequently, precise control of the spot size is required for accurate micromachining. A poorly controlled spot size can result in larger features widths and increased sloping of the side walls. The smallest obtainable spot size determines the minimum feature size, which is limited to half the wavelength of the hght used. Under the conditions where a perfect lens with no spherical aberration is used to focus a laser beam that is collimated, the minimum diameter of the focused laser beam is given by... 

There is an optimum angle, as indicated by wave optics. For example, the effect of spherical aberration of the objective is to distort the wave leaving the specimen from the spherical shape produced by a perfect lens. This vmwanted extra pathlength PD inserted into the wave is given by... 

Aberration A perfect lens would produce an image that was a scaled representation of the object real lenses suffer from defects known as aberrations and measured by aberration coefficients. 

Unlike the designs with rectangular lens expanding chambers discussed above. Song et al. proposed a design with a circular chamber to realize a perfect lens profile [16]. They presented a mathematical model to describe the relationship between the lens shape and flow rate. Their circular chamber is shown in Figure 7.12 [16]. The relationship between the flow rate ratio and focal length of the symmetrical double convex optofluidic lens was ... 

With a perfect lens, this function is symmetric along the optical axis [11]. The three-dimensional analytical formulation of the PSF for a perfect, ideally corrected and aberration-free objective is given by [6,13]... 

Spherical perfect lens Solutions of Maxwell s equations for spherical geometry, S. A. Ramakrishna and J. B. Pendry, Phys. Rev. B, 2004, 69, 241101. 

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