OK, then what's an example of a useful optical device that gets the device
within a 100 or 1000 nanometers of say something in the visible spectrum,
or some other part of the spectrum? Maybe this is another way of also
asking what's close in the case of the visible spectrum? Not being real
familiar with microscopes, I would think that common ones operate within
1/4" or so of the object. Electron microscopes?

Marc Reinig wrote:
"W. Watson" <wolf_tracks@invalid.com> wrote in message
news:A1oBj.15662$Ej5.2728@newssvr29.news.prodigy.net...
It seems then that there really is no practical applications yet for
this idea, particularly not astronomy or even biology (microscopes).

Biology yes, astronomy no ;=)

By near field, it is basically meant optics used close to the object of
interest?

Sort of. It means you need to interact with the near field effects near
the object (hence the term near field). Their intensity decreases
exponentially with distance. However, the optics observing the result of
the interaction can be far away (relatively), since the interaction
results in radiating fields: light as we generally perceive it. Near
field interactions must be within ~wavelength distance (typically much
less).

On Mar 11, 9:39 am, "Charles Manoras" <inco...@cette.adresse> wrote:
"Helpful person" <rrl...@yahoo.com> wrote

There is a configuration that does not limit resolution by the optical
aperture (diffraction). In materials with negative refractive index
(the rays are refracted to the "other" side of the surface normal) it
can be shown that there is no limit to the resolution.
Although such materials do not exist in nature they have been
constructed using repetitive layers of LC (inductance, capacitance)
micro circuits. These have been built and demonstrated using visible
light.
Yes I have read that several times and puzzled over this ever since.

Save me a Google search, any credible reference? Thanks.

I attended two lectures at the University of Michigan on this topic
and saw pictures of demonstrations. This was about 18 months ago.
One (the better) was by someone from England (unfortunately I forget
their details) and the other was through the local OSA by Anthony
Grbic who is presently at the University of Michigan where they are
researching into making thes "metamaterials".

It turns out that if one performs rigerous diffraction analysis that
the NA of the converginf beam no longer limits resolution.

A search on metamaterials has a lot of hits.

However, you can also use a prism and shine a beam into it. Under total
reflection, there is an evanescent wave at the air-glass reflecting
interface. If this interface is placed near the core of a fiber (within a
wavelength but not touching and assuming the fiber can support a mode for
the light) the wave will coupled into the fiber and propagate.

I'm browsing through Goodman's Introduction to Fourier Optics, and noticed
the topic in the Subject above in sections 6.6, p160f, 2nd edition. The math
is a bit above my current experience, but what devices does this apply to?
What are the applications? A subtopic is extrapolation method based on
sampling theorem.
--
Wayne Watson (Nevada City, CA)

Web Page: <speckledwithStars.net

"Marc Reinig" <Marco@newsgroups.nospam> wrote in news:47d6d523$1@darkstar:

However, you can also use a prism and shine a beam into it. Under total
reflection, there is an evanescent wave at the air-glass reflecting
interface. If this interface is placed near the core of a fiber (within
a
wavelength but not touching and assuming the fiber can support a mode for
the light) the wave will coupled into the fiber and propagate.

So, does all the light couple? If so, I presume the total reflection
disappears.

Also, is this more advantageous than direct coupling with a lens?
I presume it must be easier to align or something?

Is there a name for this technique so I can go Google it?

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

In evanescent coupling, if you misalign, less than optimal coupling is
achieved and the energy not coupled is just reflected (where presumably
you have an absorber any way) and no energy is coupled to places you
don't want it coupled.

"Marc Reinig" <Marco@newsgroups.nospam> wrote in news:47d813e7$1@darkstar:

In evanescent coupling, if you misalign, less than optimal coupling is
achieved and the energy not coupled is just reflected (where presumably
you have an absorber any way) and no energy is coupled to places you
don't want it coupled.

Thank you much for the info. Being just a hobbyist, I enjoy
learning new stuff.

Just one question. For this evansescant coupling technique, do
you still focus the beam down like in regular coupling? I presume
the spot would be focused on the TIR surface of the prism?

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

"rge11x" <rge...@netscape.net> wrote



This is a very good review of the subject

Colin Sheppard: "Fundamentals of superresolution"
Micron 38 (2007) 165-169
doi:10.1016/j.micron.2006.07.012

I do not understand your reference.

Is this a magazine?

What's the mysterious code on the second line?

This is a very good review of the subject

Colin Sheppard: "Fundamentals of superresolution"
Micron 38 (2007) 165-169
doi:10.1016/j.micron.2006.07.012