High resolution extended image near field
optics
7. Further comments
[this page | pdf | references | back links]
Copyright (c) Malcolm
Kemp 2010
Return
to Abstract and Contents
For photolithography and perhaps also for some types of
microscopy, having an image the same size as the object is not necessarily a
fundamental problem. However for telescopy and most types of microscopy it is.
Objects we are interested in viewing through telescopes are typically large and
far away, whilst objects we are interested in viewing through microscopes may
not be far away but usually we want to incorporate some magnification into the
process.
It is possible to create aplanatic analogues of double
confocal and coaxial ellipsoids introduced in Section 2 that still
span the complete range of angles onto a plane, and can thus still in principle
make use of nearly fully silvered plane mirrors to support imploding dipole
wavefronts. Indeed, the main reason I was led to explore the exact behaviour of
solutions to Maxwell’s equations was because I had been considering the
possible use of such mirror layouts for solar power concentration
and solar
powered flight purposes.
However:
(a) Whilst
equivalent aplanatic layouts that involve magnification can be identified, they
do not appear by themselves to create the required boundary conditions to
generate perfectly imploding dipole solutions. Instead it seems to be necessary
to rotate (and attenuate) by different amounts the light falling on different
parts of the telescope or microscope aperture in order to achieve the desired
boundary conditions.
Such an analysis highlight that is the
presence of the plane mirror at the image plane which is of particular
importance in achieving superresolution, as we might have surmised from the
discussion in Section 6
about how and why this sort of superresolution does not contradict established
physical principles.
(b) For astronomical
telescopes, it does in principle appear to be possible to achieve a resolution
better than that implied by the Rayleigh resolution criterion, by linking two
such devices as in (a) of different sizes back-to-back to achieve a suitable
level of magnification. However, it is doubtful whether such a device would be
as effective as one that involved multiple individual telescopes positioned
some way away from each other, which is a well-established technique for
boosting resolving power. In particular, we noted in Section 6 that the
improvement in accuracy arises principally because we are discarding most of
the light falling on the layout, impairing such a telescope’s light gathering
ability.
NAVIGATION LINKS
Contents | Prev | Next