Science-Related Photos: Post & Share Yours!

[Andy Resnick]

A colleague here buys scrap wafers for use as substrates- they are super-flat, clean, and absurdly cheap. He gave me one to play around with, and here's the results.

First, oblique illumination- some gooseneck lighting off to the side, using a 4x epiplan:

http://a.imageshack.us/img580/2899/dsc00720u.jpg
http://a.imageshack.us/img64/7389/dsc00723z.jpg

Two points to note: First, the etchings act as (reflection) diffraction gratings, and second, the color changes with rotation angle.

Now a photo combining oblique and epi-illumination (8x epiplan): the field stop was closed down quite a bit, and the contrast is tough because of the difference in illumination.

http://a.imageshack.us/img204/9158/dsc00731pk.jpg

The difference in imaging is striking- there is no color in epi-illumination, and the contrast is reversed. This is why I have had problems taking pretty pictures using epi-illumination, unless other contrast methods (such as DIC) are employed. The other common epi-illumination contrast method is darkfield, and here's an image taken using a 16X epiplan HD (darkfield) objective- this is a 100% crop:

http://a.imageshack.us/img201/7274/dsc00729j.jpg

Clearly, I'm having trouble getting a finely focused image- the viewfinder just isn't good enough, as these fine details are not visible though the viewfinder.

 

[Andy Resnick]

Upon Andre's suggestion, I've tried playing around with an 'extended depth of focus' algorithm. Similar to (confocal) microscopy image stack manipulation, the idea is to take a large number of photos and assemble together only the 'in focus' portions, resulting an an image with both high resolution and large depth of field: two optical properties that act in opposition.

I took a series of images of a 1/32" ball bearing resting on foam, using my 25 mm luminar and my 16mm luminar, and these are the results:

(16mm)
http://a.imageshack.us/img839/254/edof16mm.jpg

(25mm)
http://a.imageshack.us/img801/8995/edof25mm.jpg

I'm not happy with the results- I think there's entirely too much high-frequency noise in the edges of the foam, which may not be clear in the scaled-down images. There are ways to adjust the algorithm- just like deconvolution, there's many, many adjustable parameters, and blindly twiddling values is an exercise in frustration.

One fun aspect to the 16mm: if you can make out the purplish disc in the dead center of the sphere, that's from the frame taken when the center of the sphere was located at the front focal plane of the lens (autoreflection), which let's me image the lens itself.

 

[Andy Resnick]

Not very science-y, but somewhat interesting.

I went deep into my back catalog, and pulled out some bullets I recovered during my time as a USAF contractor- these were lying all over the place, from live-fire exercises. I don't know what type they are, but they weigh about 420 grains, which I think makes them 50-cal, probably vehicle-mounted..

As for science, call it a study in plastic deformation. Also, the high-magnification shots look very similar to modeling clay/moonscapes.

[PLAIN]http://a.imageshack.us/img844/4383/dsc20531.jpg

[PLAIN]http://a.imageshack.us/img837/5718/dsc20561.jpg

[PLAIN]http://a.imageshack.us/img294/9962/dsc20591.jpg

 

[Andy Resnick]

I had a few minutes to play around this week- I took some color interference photos of water on glass using the microscope (10X lens here)

[PLAIN]http://img814.imageshack.us/img814/7117/interference2.jpg [PLAIN]http://img258.imageshack.us/img258/9573/interference1.jpg This is a small section of the whole frame.

This is a variation of the method we developed back at NASA to image fluids in the vicinity of a contact line as part of a dynamic wetting experiment. The fringes indicate the local thickness of the water, and it's possible to measure the absolute thickness to fairly high accuracy. There, we used a monochromatic source and broadband mirrors instead of the dichroic filters normally present in fluorescence cubes to illuminate the sample.

Here, I used the broad-band output of a metal halide lamp through a five-color (Sedat) cube. The cube doesn't have any excitation filters- those are mounted back at the source. The dichroic mirror and emission filters are designed to allow fluorescence with multiple fluorochromes, and without using an excitation filter to select a particular color, I can basically use the cube as a broadband mirror.

An important point is that the source is fiber coupled- this increases the spatial coherence, which improves the fringe visibility. If I had an aperture stop in the epi-illumination path, I could probably increase the contrast even more.

 

[fuzzyfelt]

Wonderful!

 

[~christina~]

I had a few minutes to play around this week- I took some color interference photos of water on glass using the microscope (10X lens here)

Very nice close up.

 

[Andy Resnick]

Thanks, guys!

 

[Andy Resnick]

Now that my proposal has been submitted, I can get back to goofing around...

I got tired of waiting for the leaves around here to change color, so I just grabbed a fresh one and took the following:

[PLAIN]http://img52.imageshack.us/img52/8748/dsc2726d.jpg

It's the underside of the leaf, taken with a 100X 1.3 water-immersion lens designed for use with no coverslip. The rectangular-ish shaped things are the stoma- one cell on each side of the opening:

http://www.palaeos.com/Plants/Lists/Glossary/Images/Stoma.jpg

I also took this image of a seedpod-type thing growing on some ornamental grass outside- the whole thing looks a bit like wheat, but up close (8X here), there's a lot of detail:

http://img829.imageshack.us/img829/1179/dsc27301.jpg

Not sure what the circular bits are- they are too big for stoma, but they look very similar.

The recent thread on the optics of diamonds, and especially turbo-1's posts, has motivated me to take a series of images of sparkly things- when I get a few decent ones, I'll post those.

 

[Andy Resnick]

Sparkly things! This has to be a quick post- I'm off to start preparations for a halloween party (i.e. test different zombie recipes...)

Minerals can create colors several different ways: reflection, absorption, diffraction, and interference (and combinations). Here's an example of each-

Absorption: This is a fluorite crystal, colored deep blue. The bright side shows a bright light incident onto the stone, and the faint purple-blue is the transmitted light. The stone normally appears opaque-

[PLAIN]http://img826.imageshack.us/img826/6415/dsc3226v.jpg

Reflection- here's the bling-bling. These are diamonds, and the bright blue facet shows how dispersion and total internal reflection combine to give little (and I do mean little...) flashes of color:

[PLAIN]http://img826.imageshack.us/img826/3106/dsc2751.jpg

Interference: these are two images of mica, showing interference effects from slight changes in the thickness of the material, or from the presence of a slight airgap inside the material.

[PLAIN]http://img576.imageshack.us/img576/3410/dsc3235i.jpg

[PLAIN]http://img513.imageshack.us/img513/9352/dsc3237.jpg

Now we come to more exotic optical effects- the first is from opal. Normally, the crystalline structure of minerals does not directly effect the transmission of light, becasue the lattice size is so much smaller than optical wavelengths. Opal is different, the material has a lattice size very close to optical wavelengths. In fact, photonic bandgap materials are often called 'artificial opal'. Notice there are only 2 colors present, and the regions correspond to defect-free single crystals.

[PLAIN]http://img263.imageshack.us/img263/7365/dsc3218.jpg

The last two images are minerals with a fibrous crystal habit. The fibers preferentially scatter light in certain directions, leading to a 'cat's eye' effect. Here's one example, I'm not sure what the mineral is:

[PLAIN]http://img808.imageshack.us/img808/9886/dsc3240.jpg

And here's tigers-eye:

[PLAIN]http://img837.imageshack.us/img837/4929/dsc3245q.jpg


Now, most of these optical effects are similar to caustics- I can capture those by imaging the back pupil plane of the microscope objective- but for whatever reason, I wasn't seeing anything markedly better than the 'regular' images. Photonic bandgap materials, in particular, have spectacular diffraction patterns.

I think I'll try imaging optical vortices next...

 

[Andy Resnick]

Sometimes frustration is a good thing.

I wasn't ready to give up trying to get high-magnification images of the tiger's-eye and the other mineral displaying a cat's-eye effect (chatoyance, if you want to toss around a $5 word). If you recall, the previous images were taken with a Luminar lens and oblique incident light- I have everything setup on my optics table like a macro setup- the lens and camera are on a rail so I can control the lens-camera distance (magnification). This is an image taken with the 16mm luminar at maximum magnification- the camera is 4' away from the lens (the lens is about 1 mm from the stone):

[PLAIN]http://img263.imageshack.us/img263/4794/dsc32471.jpg

This is *way* beyond the design parameters for the lens. Plus, the focus capability of my rail isn't ideal, and since the stone is 4' away from the camera, there's no good way to perform fine positioning etc. The problem was, if I take it over to the Ultraphot and perform incident light imaging, this is what the stone looks like:

[PLAIN]http://img442.imageshack.us/img442/1776/dsc3250.jpg

Here, the incident light is co-linear with the imaging pathway (epi-illumination). The polished surface dominates the image, and since the optical effect comes from scattering within the bulk, none of the beautiful structure is visible.

In a fit, I put on a darkfield objective. Previously, I had only used this to image mirrored surfaces- darkfield imaging tosses out the unscattered light, leaving only light scattered from surface defects. Here's what the stone looks like at 16x darkfield- first, a whole-field image and then a 1:1 crop:

[PLAIN]http://img51.imageshack.us/img51/5544/dsc3249.jpg

[PLAIN]http://img577.imageshack.us/img577/4984/dsc32491.jpg

Yay! success! The individual asbestos fibers are clearly visible.

Now, onto the other stone:

[PLAIN]http://img703.imageshack.us/img703/6260/dsc3253.jpg

Notice the twinning structure, which is why this stone gives a crossed pattern.

While I had everything setup, I snapped a few pics of a cut geode: note, on the 1:1 crop, the color bands are is actually due to small spherical inclusions.

[PLAIN]http://img51.imageshack.us/img51/5081/dsc3256.jpg

[PLAIN]http://img181.imageshack.us/img181/2743/dsc3257.jpg

[PLAIN]http://img513.imageshack.us/img513/3849/dsc3260.jpg

Unfortunately, I only have the 16X HD epiplan- not sure I want to spend the cash to get more- they are a few $h each.

 

[ZapperZ]

Cu metals, especially thin-film deposited Cu, can be very smooth. However, the smoothness depends very much on the substrate and the type of deposition.

Here, Cu film was deposited using DC sputtering technique on Al2O3 (Alumina). I had the task of looking at the Cu-Al2O3 interface to see if they both bond to each other, and to look at the Cu surface. This is an SEM image of the Cu surface, showing the surface roughness. The surface is also a very disordered polycrystal.

This is the straight-on image at a higher resolution.

Zz.

 

[Andy Resnick]

Those are cool! Did that sample undergo any sort of annealing/dewetting/coarsening before the image was acquired? What's the significance of the rough texture (the fine scratchy-type features)?

 

[ZapperZ]

Those are cool! Did that sample undergo any sort of annealing/dewetting/coarsening before the image was acquired? What's the significance of the rough texture (the fine scratchy-type features)?

I don't know what caused the fine scratch. This was on an inside surface of the alumina tube, which was where the Cu was deposited. It could easily be the handling of the material after it was cut. Yeah, I had to have it cut to be able to do an SEM on the inside surface, obviously.

But then again, when Cu was deposited, they did not heat the alumina. When metal thin film are deposited "cold", they tend to have a huge amount of lattice strain that will eventually cause it to crack and stuff. So that could also be a possible source of these scratches.

Zz.

 

[Andy Resnick]

interesting... since there's a cut edge, have you taken a look at the cross-section, just for fun?

 

[ZapperZ]

interesting... since there's a cut edge, have you taken a look at the cross-section, just for fun?

Yes. Unfortunately, it was cut using a diamond saw, and the cut edge is very "disturbed". I can't tell what is "native" and what is due to the cutting process.

Zz.

 

[Astronuc]

Cu metals, especially thin-film deposited Cu, can be very smooth. However, the smoothness depends very much on the substrate and the type of deposition.

Here, Cu film was deposited using DC sputtering technique on Al2O3 (Alumina). I had the task of looking at the Cu-Al2O3 interface to see if they both bond to each other, and to look at the Cu surface. This is an SEM image of the Cu surface, showing the surface roughness. The surface is also a very disordered polycrystal.

Zz.

What device/system was used to obtain those images?


On a bigger scale -
http://news.nationalgeographic.com/news/2010/10/photogalleries/101104-best-space-pictures-station-earth-sun-storm-mars-118/

 

[ZapperZ]

What device/system was used to obtain those images?

A standard "table-top" SEM system.

Zz.

 

[ZapperZ]

One of the things I study is RF breakdown, either in vacuum or in a medium in vacuum. This is a case of the latter.

This is an SEM image of a butt-joint between two cylinders made of Al2O3. No matter how smooth or how flat one makes a surface, the joint typically has the highest field due to the presence of a minuscule gap. So this is where many sparks and breakdown effects take place. This SEM image shows the surface at the end of the cylinder. The wormy-looking channel, we believe, was made by the electrical sparks that when through the thickness of the joint.

Zz.

 

[Andy Resnick]

Singularities often occur in optics. Caustics- the bright lines at the bottom of a swimming pool, the sparkles of sunlight off water, the canonical pattern in a coffee mug- are all singularities, also called a 'diffraction catastrophe'.

The usual argument is that diffraction effects prevent an infinite intensity from actually occurring. That may be true, but it's possible for light to also have a singularity in *phase*. In this case, the phase is indeterminate and the intensity is identically zero. These singularities are called 'wave dislocations' and are stable.

It's fairly straightforward to make an optical device that creates these singularities:

http://www.phy.bris.ac.uk/people/berry_mv/the_papers/Berry303.pdf

Here's some images I took yesterday:

[PLAIN]http://img441.imageshack.us/img441/8179/dsc3305g.jpg

[PLAIN]http://img230.imageshack.us/img230/7820/dsc3298e.jpg

[PLAIN]http://img181.imageshack.us/img181/3909/dsc3297.jpg

The interpretation of these conoscopic patterns is incredibly complex- for example, the line bisecting the bulls-eye pattern in the last image is a singularity, the intensity is zero and the phase is indeterminate- Berry calls this feature a 'fermion brush'. The pattern itself is 'a nontrivial square root of zero'.

The middle image is still not understood- the fermion brush should still bisect the bulls-eye instead of the isolated dark point (the central peak is not the actual center of the bulls-eye).

 

[Andy Resnick]

A colleague gave me some spare germanium that he was using to fabricate something or another. The pieces gave me some excellent images using reflected DIC: These are all at 16x, except for the last one (40x).

[PLAIN]http://img688.imageshack.us/img688/5174/dsc3815z.jpg

[PLAIN]http://img813.imageshack.us/img813/5097/dsc3817.jpg

[PLAIN]http://img529.imageshack.us/img529/5946/dsc3820d.jpg

[PLAIN]http://img63.imageshack.us/img63/3388/dsc3823.jpg

[PLAIN]http://img607.imageshack.us/img607/7985/dsc3824.jpg

 

[turbo]

Nice shots, Andy. I missed the refractive effects from November, and those are quite interesting.

 

[Borek]

Critical angle in a cheap plastic prism.

Walls are not perfectly flat (you know, cheap plastic) so I had to Photoshop it a little bit

 

[Andy Resnick]

Borek- very nice!
You just (re)invented the Abbe refractometer... :)

 

[Andy Resnick]

It's funny how things work- months go by with nothing good to photograph, and then a week of 'hits'.

I found, for lack of a better word, a 'thing'. It's a piece of a diffractive optic- the kind that makes different images as you tilt it. Not a hologram!

Here's the front taken at two different angles with respect to the lens:

[PLAIN]http://img809.imageshack.us/img809/949/dsc4563.jpg

[PLAIN]http://img844.imageshack.us/img844/5606/dsc4562e.jpg

You may have seen these things- in this case, there are balloons that move across the field as the tilt angle is changed.

I wanted to see how they work, so I put it under the microscope and tried a few different illumination methods- crossed polars worked perfectly. Here's some magnified shots of the base of the balloons:

[PLAIN]http://img846.imageshack.us/img846/6433/dsc4566.jpg

[PLAIN]http://img852.imageshack.us/img852/756/dsc4567.jpg

[PLAIN]http://img856.imageshack.us/img856/6614/dsc4569.jpg

Pretty!

 

[Andy Resnick]

I'll have a few interesting photos shortly- here's a random one in the meantime:

[PLAIN]http://img546.imageshack.us/img546/9513/newout99999dostack101.jpg

Andre clued me in about 'focus stacking'- I am used to taking image stacks and then deconvolving them as part of my research, and focus stacking is a simplified version. For focus stacking, I use Combine ZP (a free program):

http://en.wikipedia.org/wiki/CombineZP

It works well, but it takes some time to understand the appropriate 'parameter space'.

The image above was taken using the 16mm luminar at a magnification of about 30X. I took about 20 images, each time advancing the sample slightly forward- each individual image has only a thin sliver of in-focus components- and then told CombineZP to put them all together.

The image is of a gold nugget (although at 30X, it's not much of a nugget). Sometime last century we took a family trip to South Africa (this was during apartheid) and we took a tour of a working gold mine. At the end of the tour, we each got to pick a rock of ore and take it home. At that time, the mine processed 2 tons of ore for each ounce of gold, and used an amazingly toxic sludge to extract the gold (I remember cyanide was involved).

That's it for now- I have another image stack cooking in the computer, and should post the results shortly. If you want to see someone who *really* does amazing things with focus stacking (among other things...), check this guy out:

http://www.flickr.com/photos/johnhallmen/

 

[Andy Resnick]

Just to close out Post #54- here's an edge-on shot of the optic:

[PLAIN]http://img862.imageshack.us/img862/8673/dsc4661.jpg

Starting at the bottom is the magnetic base, the bright layer is (I think) simply a highly (diffuse) reflective layer on which the ink is printed (the colored dots). Finally, on top, are the molded plastic cylindrical lenses. Maybe I'll try cutting off the plastic to see what the printed pattern looks like.

 

[kland1]

Come on, I know I'm not the only person with scientific photos lying around. I know there are other scientists around here.*looks under some rocks (but only finds some earthworms)*

Post post post!

Hello I have spent the last few years working on a Tesla Turbine and even though I'm not in a science lab I am wearing a lab coat so that should count right?

So here is a photo pallet of science pictures on the turbine work, http://www.seabirdadventure.com/photos/the-tesla-turbine

I will attempt to attach a couple of lower res pics in this post.

Kris

 

[Andy Resnick]

I like the image of a flame (is that right?)- how did you take it?

 

[kland1]

I like the image of a flame (is that right?)- how did you take it?

Hello Andy, thank you.

Actually I'm not sure where I dug that picture up, It was sometime last year when I was working on the Tesla Turbine, I'll include a pic of it running here in this post. Also If you would like to read about the testing , http://www.seabirdadventure.com/tesla-turbine/tesla-turbines-are-very-different , that went into it for the last four years or so.

However the picture is the Turbine running on 90% H2O2 instead of flame so the picture is not from this test for sure.

Let me know if you'd like to see any more pics.

Cheers, Kris

 

[Andy Resnick]

I put a small piece of those cheap transmission gratings (we have
them lying around for K-12 outreach):

https://www.amazon.com/dp/B001DSGYEO/?tag=pfamazon01-20

in the filter holder of the 15mm and got this:

http://img560.imageshack.us/img560/9092/dsc6569c.jpg

I like the effect; I'll have to play around with this some more...