View Full Version here: : Counterintuitive Light
23-11-2011, 08:06 AM
Take a look a this …
Blocked holes can enhance rather than stop light going through (http://www.physorg.com/news/2011-11-blocked-holes.html)
How much more light ?
70 percent more !
Try predicting that from 'first principles' !
I suppose once it is known that this is how it works, it can then be 'predicted' from theory … chuckle, chuckle … ;)
How does it happen ? (Here comes the theoretical 'prediction' …)
Talk about counterintuitive !! And this time, the unanticipated result has been exposed via experimentation.
I wonder how many 'intuitive' expectations end up being incorporated into theoretical predictions, entirely due to unconscious/unchallenged/unsupported (empirically) 'intuition'?
.. Great stuff !
23-11-2011, 09:15 AM
so what would happen if you have a series of these holes with each enhancing the output from the previous? or does it only work with coherent light, and the output is a bit scrambled?
23-11-2011, 09:39 AM
I'll have to confess that in spite of the views expressed in my OP, I think I'd have to guess that this effect is more a function of clever engineering, than necessarily an unexpected fundamental property of light.
It looks as though the interference patterns around the hole/cap interface acts constructively, provided the ratio of hole diameter/cap diameter, gap size, and hole spacing, are all engineered specifically to get the increased light levels. They could probably engineer these dimensions to obtain the opposite effect .. ie: increased blockage of light.
What you question … seems to be about altering the dimensions even more, altering the light coherency/source, and aligning the holes/caps specifically to maybe amplify the effect even more. I guess this could be done .. but it would have to be a matter of tuning the device to get the desired effect (whatever that may be).
I guess my point about the thread, is that one usually expects that if a light gap is plugged, it will block out the light. At this level of granularity of detail, the results seem almost inconceivable. I think the level of detail is the difference maker here.
Microscopic details can make the macroscopic world seem counterintuitive.
… A very easy factor to forget in science !
23-11-2011, 10:22 AM
There are are lot of unanswered questions.
For example did they experiment with different frequency lasers?
Did the transmitted light undergo a frequency change?
Why are electrical engineers dabbling in science (sorry only kidding.:lol:)
The answer to the second question in particular might provide hints as to what is going on here.
23-11-2011, 10:58 AM
I can not see anything about this counterintuitive, but it may be that my intuition is bit funny. If the light is an electromagnetic radiation it should be possible to design antenna for it that exhibits a gain (same as with all lower frequency electromagnetic radiation). I agree with Craig it is engineering solution.
23-11-2011, 11:00 AM
They have just discovered plasmons I think. It has been known since the 1930's that the transmission of visible light and its colour is due to small spherical grains of gold in thin films less than 100nm. Thin films are made of these discrete grains as they grow from the first atoms to 'stick' to the substrate. The red colour in red glass comes from gold particles in the glass.
You are correct sjastro they should better specify what wavelength etc is involved.
A cursory search revealed this old gem
23-11-2011, 11:01 AM
Hmmm … their website says:
Haven't found the paper yet .. but 'twould be an interesting one.
See my new avatar …
Actually, I'd say the answer to the third question is that they want answers .. not more questions !
;) :lol: :)
23-11-2011, 11:14 AM
Because if they did not all of you scientists would be still using pencil and paper for your calculations (that is if you could manufacture it) :lol:
23-11-2011, 11:17 AM
Paper is here. (http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-21-21098)
23-11-2011, 11:23 AM
Yeah, like the electric universe provides the answers.;)
It's good to see electrical engineers putting Euler's equation to good use.:thumbsup:
23-11-2011, 11:33 AM
Just kidding around with the Avatar …. 'twas "gimmick" infringement so I've reverted back to the Lorentz Attractor !
Looking at the paper, figure 4 shows the comparison of transmittance vs wavelength .. its an interesting relationship.
They definitely say its due to the 'antenna effect' which enhances Raman scattering:
23-11-2011, 11:49 AM
Yep .. you're right here Bert.
They're playing around with the tunable parameters to optimise the retransmittance and reflectance amplitudes (by wavelength).
They vary the hole and gap size and provide simulations showing what happens if other structures (like a bar) is introduced (under one end of the 'cap').
All engineering stuff. Very interesting. Has military applications also, I notice … (like enhancing sensitivity to sniffing out explosive molecules).
23-11-2011, 02:30 PM
Very interesting paper Craig which incorporates ideas from quantum physics (Raman scattering), solid state physics (dielectric breakdown or antenna effect) and plasma physics (plasmons).
And all compiled by electrical engineers.:eyepop:
23-11-2011, 02:36 PM
If we scientists didn't provide you with the necessary tools such as the equations, you engineers would be as useful as a screen door on a submarine.;)
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