Behavior of light in a prism filled with oil and many, many tiny prisms

[Canai]

So I was chatting with my microbio prof during lab today about the effects that the oil immersion has on the light traveling through the slide and to the objective lens, and eventually it came to me wondering if a clear, say glass, empty prism was filled with oil would have the same refractive properties that a solid glass prism would. Going a bit further, I wondered what would happen if you were to to take the oil filled prism and add many tiny, perhaps almost microscopic triangular prisms to it, turning it into a homogeneous solution filled with little glass pyramids. She had no idea, but will pose the question to some of the people in the physics dept.

So does anyone work with light here? What kind of refraction would that have, using either white light or a laser?

I'd think that it would tend to fill the overall prism with the light, refracting it at random out of all the sides. I wonder if some of the refracted light would recombine and come out in it's original state, or if it would just be all random.

I think this is the right place to post this, and I'm looking forward to the standard ATOT answers

P.S. Feel free to just tell me I'm an idiot and shouldn't dabble in science if you'd like :laugh:

 

[Thegonagle]

I think the light would mix back into white light, assuming such microscopic prisms.

Just my first guess though. I'm no physicist.

 

[nakedfrog]

I'd suggest Highly Technical.

 

[Canai]

Originally posted by: nakedfrog
I'd suggest Highly Technical.

Would a mod kindly move this there? I guess I fail at reading, since I looked for HT but didn't see it on the list

 

[Rubycon]

Refractive index of common substances

Many prisms would just create lots of reflections within.

Of course this doesn't take into consideration the coherence, chromacity and width of the source.

 

[imported_Tick]

Um... Why? I'm an optical engineering student, so I can probably figure out what your asking, but I'd need a diagram of WTF your talking about.

 

[nakedfrog]

Originally posted by: Rubycon
Refractive index of common substances

Many prisms would just create lots of reflections within.

Of course this doesn't take into consideration the coherence, chromacity and width of the source.

You're actually an advanced android, aren't you?

 

[Canai]

Originally posted by: Tick
Um... Why? I'm an optical engineering student, so I can probably figure out what your asking, but I'd need a diagram of WTF your talking about.

It was just something I was wondering about.

You have three prisms, one made of solid glass, and the other two are empty glass shells, both of which are filled with oil (what kind, I have no idea ), and one of the oil filled ones is a homogeneous solution with tiny triangular glass prisms in it. You place each of them in front of a light source, one white light, the other a laser (again, no idea what kind ).

What happens in each case (when viewed through a spectrometer)? Obviously the solid glass prism will refract the light as one would expect it to, but what about the other two cases?

Thanks for bearing with my lack of knowledge about this

 

[Rubycon]

Originally posted by: nakedfrog


You're actually an advanced android, aren't you?

I've got an advanced degree in cybernetics. Is that good enough?

Who needs a prism when you can have this?

 

[Canai]

Originally posted by: Rubycon

Originally posted by: nakedfrog


You're actually an advanced android, aren't you?

I've got an advanced degree in cybernetics. Is that good enough?

Who needs a prism when you can have this?

How??

 

[imported_Tick]

Originally posted by: Canai

Originally posted by: Tick
Um... Why? I'm an optical engineering student, so I can probably figure out what your asking, but I'd need a diagram of WTF your talking about.

It was just something I was wondering about.

You have three prisms, one made of solid glass, and the other two are empty glass shells, both of which are filled with oil (what kind, I have no idea ), and one of the oil filled ones is a homogeneous solution with tiny triangular glass prisms in it. You place each of them in front of a light source, one white light, the other a laser (again, no idea what kind ).

What happens in each case (when viewed through a spectrometer)? Obviously the solid glass prism will refract the light as one would expect it to, but what about the other two cases?

Thanks for bearing with my lack of knowledge about this

Ok... Obviously, the first prism works just like you'd expect it two. With the second prism, you get two more opportunities for refraction, so your going to get more refraction of the light. So you'd get a larger 'rainbow' effect, as well as a greater bending of the incoming light beam. With a laser, of course, you get no rainbow pattern as you only have a single wavelength. I'm assuming were talking about a relatively ideal situation, with well-columated beams of light.

For the third example, theres a whole bunch of possibilities. I'd think with enough prisms, you'd get essentially even distribution of light out all the faces. As the number of prisms aproached infinity, and assuming they're not all aligned the same way, there would be white light dispersed evenly on all faces. This is ignoring absorbtion, of course. If we all for absorbtion, with enough prisms, there would be no, or virtually no, light exiting the system.

 

[CycloWizard]

White light goes into a prism and separates according to the speed of light of each wavelength in the medium (called 'chromatic aberration'). If the refractive index (which is directly related to the speed of light of a given wavelength in the medium) is constant everywhere in the medium, then the light travels a straight path until it finds a medium with a different refractive index. When it finds this new barrier, the chromatic splaying (not sure what to call it) changes depending on the difference in refractive index between adjacent media.

So, the answer to your question, as with any good question, is that it depends. Red light has a high wavelength, indicating a relatively low energy density. Therefore, I'll guess that its speed of light in a given medium is lower than, say, violet light (I'm not sure this is true, but it makes sense based on my minimal knowledge). Snell's law tells us that r=(ni/nr)*i, where r is the refracted angle from the surface's normal, nr is the index of the medium which the light is passing into, ni is the refractive index of the other medium, and i is the incident angle relative to the surface normal. So, on the outside, ni is approximately the same for all wavelengths (refractive index of air is about 1.000006 IIRC). Thus, the refracted angle increases as the refractive index gradient increases. Since n=v/c, where n is the refractive index, v is the velocity of light in the medium, and c is the velocity of light in a perfect vacuum, it is then clear that the refractive index of red light will be less than that of violet light for a given medium. Now the question is: by how much? That depends on the material's optical properties. So, hopefully my gibberish helps make a little sense of how you would figure this out if you knew a little bit more about the stuff you were building these magical prisms out of, but probably it just confused you more.

 

[ScottMac]

Immersion oil is used to reduce the refraction, diffusion, and diffraction of the illumination from the slide into the objective of the microscope.

For ultimate resolution and best imaging for most biologicals, also reveiw setting your microscope properly, using Koeller Illumination:

Koeller Illumination ...

(from here on, assume white light source)

In some cases, you also have a drop of oil between the light source and the bottom of the slide (this is fairly rare).

The refraction occurs because of the different refractive index of air and glass (or air & plastic, or air & water, water & glass, glass & plastic ... all have different refractive indices).

You will see some "bending" of the light any time it passes from one medium to another with a different RI. You will also get a certain amount of reflection, which is why "coated" optics perform better than uncoated optics.

For the scenario you proposed, a prism-shaped container filled with immersion oil, you would see diffraction commensurate with teh difference in the RI of the materials used. IF, for example, you could find a container and oil with (exactly) the same DI as air, you would see the light pass through with no changes.

The more likely outcome would be a primary diffraction / rainbow that would be of "lower quality" (less sharp, fuzzy) than a normal glass triangular prism, with other smaller rainbows. You would get the primary effect from the entire prisn-looking thing, then you'd get other diffractions from the air-plastic interface of side A, the plastic-oil interface on the inside of side A, the oil-plastic interface of side B, then the plastic-air interface on the outside of side B.

The degradation would occur as the result of the four different RI interfaces, plus the degradation from contaminants in the oil and plastic.

Adding a bunch of little mirrors or prisms into the oil would just degrade the primary diffraction. It would be a little more exciting if you aimed a laser through it, but probably not as exciting as putting a laser through a crystal.

The whole diffraction thing is explained as being like a line of soldiers, with tallest at one end, to shortest at the other. The line is ordered to march through an area of deep mud. The longer-legged soldiers (red light) have less of a problem with the mud and move through faster; the shorter-legged soldiers (blue light) are bogged down more and negotiate the mud slower. The resultant skew in the line represents the defraction of the various colors of light passing through (in this case) a prism. Red light is bent less than blue light. Red Orange Yellow Green Blue Indigo Violet (Roy G Biv) in that order.

I'm not a scientist; I don't even play one on TV, but the above is my recollection from having worked at Carl Zeiss for a couple years, a long time ago.

Good Luck

Scott

 

[Rubycon]

OP: If you use a laser (monochromatic source) on a prism you will not see any other colors since there is only one. I actually have people ask me about (using a gel to change laser color!) so I show them - green light goes into red gel and green light comes out and they are amazed. :laugh:

White lasers are available too just combining several lines and these are as fun to experiment with as they are costly.

My latest "toy" is a BluRay laser - a diode from a PS3 mounted in a tiny 1AAA flashlight body. Its center is ~405nM and appears quite weak to human eyes but will make lots of things fluoresce brilliantly just as blacklight does. It's supposed to be great for tack welding with UV curing adhesive but I have not tried it yet.

Laser experimenting can be fun as long as follow the cardinal rule - never stare into the laser with your remaining eye!

 

[Canai]

Thank you everyone for your posts!

I think it would be interesting to use a laser with the tiny prism / oil solution.

On a semi-related side note, could anyone explain the whole 'shifting image' security feature of the new $100US bills that are coming out next year? I read something about them having all these little lenses on them, and an image that would shift depending on how you held the bill.

 

[oldman420]

I remember way back in Portland Or I was in a coffee shop and saw a lense made of a liquid filled plexiglass shell it employed a double convex curved lense effect to produce amazing photos it was 12" x 12" the fluid within deff interacted with the photons in the same way as would a solid glass lense would have, howeverI imagine the effect was somehow caused by the liquid. the photos were directly exposed to very large paper and had a sureal 3d effect to them you could really almost reach into them.