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UltravioletPhotography

Examples of photographs throughout the entire electromagnetic spectrum


Pylon

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I know reflective UV-A, VIS, and IR-A photography is possible with common sensors that are in DSLRs, and that reflective IR-B photography is possible with other sensors (although I don't remember the site of where those are being sold and how much they were), and that transmitted x-ray photography is possible, but what about reflective gamma, xray, IR-C, UV-C, microwave, and radiowave photography? Is that possible somehow? If so... is it possible to record images of objects and landscapes? Where can I find some examples of this? Post any examples/hyperlinks of these unexplored categories down below!

 

Also, is Infrared Induced microwave Fluorescence Photography possible? or microwave induced radiowave fluorescence photography? the possibilities are so many I am getting excited! what about IR-C photography? Could you see through objects with that? Where can one find IR-B and IR-C imaging systems (cameras/lenses/sensors)? Or reflective UV-C imaging systems?

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Hah, this is my bag.

 

For microwave imaging, you need an imaging microwave radiometer. I am quite interested in building one of these someday, since buying one is way outside my price range. But that is a long term project. One problem with microwave imaging is that microwaves are quite large, ranging from millimeters to centimeters, and the diffraction limit prevents one from ever getting a truly sharp image. You can never see, in principle, details that are smaller than the wavelength[*]. This tends to rule out imaging using radio waves also, since radio wavelengths are in the METER range, so the objects you are photographing have to be hundreds of meters high to make it worthwhile. Good for astronomers but not for us.

 

This paper discusses microwave radiometry aka microwave cameras:

http://www.qucosa.de...FMN07_II_C1.pdf

 

From the paper, here is an image:

post-94-0-81477300-1453417872.jpg

Interesting feature: notice that the ground seems to behave as a giant mirror.

 

Between microwave and long wave infrared is terahertz imaging, which is popular with governments for seeing people naked to make sure they have no weapons. You may google search for the naked people images yourself.

 

For the long wave infrared (thermal wavelengths, 8-13 microns), I have a thermal camera. You can see my pics here.

 

SWIR cameras, in the 1500 nm range, are relatively affordable and I want one. Possibilities include these two links:

http://www.edmundopt...d-cameras/2418/

http://www.infraredl...ve_Camera.shtml

 

Silicon is fine for imaging near infrared through near UV, and I think we have that covered here. I am not sure how to image UV-B (although I'm certainly interested). One thought I've had is to make a zone plate and just take crazy long exposures. One probably needs a large sensor for this.

 

Gamma ray cameras are unaffordable, you need a source of gamma radiation, and dangerous to play with for obvious reasons. They use pinhole camera type setups rather than lenses, since gamma radiation is not refracted by much.

 

[*] Subject to a whole host of exceptions to the rule, like near-field imaging, metamaterial lenses, and other topics of current research.

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I thought gamma-ray cameras used long-focal-length pass-through Fresnel mirrors rather than pinholes (much bigger aperture that way.)
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Well, I admit I've only read wiki on this, but I thought they used collimators, which are more akin to pinholes?

The conventional method is to place a collimator over the detection crystal/PMT array. The collimator consists of a thick sheet of lead, typically 25 to 75 millimetres (1 to 3 in) thick, with thousands of adjacent holes through it. The individual holes limit photons which can be detected by the crystal to a cone; the point of the cone is at the midline center of any given hole and extends from the collimator surface outward. However, the collimator is also one of the sources of blurring within the image; lead does not totally attenuate incident gamma photons, there can be some crosstalk between holes.

Unlike a lens, as used in visible light cameras, the collimator attenuates most (>99%) of incident photons and thus greatly limits the sensitivity of the camera system. Large amounts of radiation must be present so as to provide enough exposure for the camera system to detect sufficient scintillation dots to form a picture.

Other methods of image localization (pinhole, rotating slat collimator with CZT (Gagnon & Matthews) and others) have been proposed and tested; however, none have entered widespread routine clinical use.

(Since I'm never going to own one, my curiosity on gamma cameras was pretty casual and I admit I didn't do as much reading on them as I have on microwaves.)

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They use pinhole camera type setups rather than lenses, since gamma radiation is not refracted by much.

 

That's certainly the conventional thought in this area, but it no longer holds true ... given some recent discoveries which have deemed these long-held assumptions as inaccurate. Alas, it has been shockingly discovered that lens elements crafted from 24-carat gold can be used to more effectively refract even gamma radiation, and therefore form sharper and more usable images!

 

Gold being a material with exceptional density, especially with regards to higher-energy radioactive bombardment (in particular, containing larger nuclei which exhibit greater quantities of electron-positron pairs, which bend gamma radiation to a higher degree), yet a very malleable material (easy to shape and mold, due to its relative softness), is the reason for its exceptional use for such a task.

 

See the link below.

 

Also, an excerpt:

 

"It is anticipated that these gold lenses will refract gamma radiation much more strongly than silicon lenses, on which physicists observed the refraction of the high-energy electromagnetic waves for the first time. The researchers thereby refuted a fundamental assumption of physics and opened up the prospect of a great many applications in medicine and materials research."

 

Gold lenses used to create gamma optics

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BTW: There are many more web resources out there, pertaining to this recent chapter in gamma-ray optics design. It's a relatively new frontier, but a very exciting one.
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I imagine that lens elements crafted from lead would exhibit similar gamma-refractive properties to gold. However, there are obvious issues with toxicity risks due to handling lead through extended/prolonged use. Which is probably one of the reasons why they went with gold, instead.
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Iggy, that's really interesting! Also a nice illustration of how risky it is to use a theory far outside the range it was originally developed to work in. Some other effect might be significant, but not accounted for in your calculation...

 

But seriously, we think quartz lenses are pricey; imagine if our lenses had to be 24K gold.

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BTW: There are many more web resources out there, pertaining to this recent chapter in gamma-ray optics design. It's a relatively new frontier, but a very exciting one.

I went looking for these web resources and I'm having trouble finding anything that doesn't refer back to the same work you quoted, from 2012. Also, the claimed result from 2012 was that the refractive index of silicon for gamma rays was n=1.000000001, which obviously is not enough to make a lens in itself. The original author of that 2012 result doesn't seem to have followed it up either, and that was 4 years ago now. I hate to say it (because it would be really cool if true), but this is looking less convincing the more I check into it.

 

Separately from this, though, I ran across a bunch of references to Laue lenses for gamma and X-rays, which seem to get a lot of search hits when I Google Scholar them. But those don't work by refraction; instead the idea seems to be to use crystals as natural diffraction gratings for the gamma and X-rays (like how they are used in X-ray crystallography) to bend the light. This is more like the zone plate idea, I think.

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I read the link Iggy provided. Interesting stuff but I'd take the information with a grain of salt. The author doesn't seem to realize one of the major components of glass is silicon. Plus I wouldn't worry about lead lenses. Lead fishing weights are safe enough to handle as long as you wash your hands.

 

Also is gamma ray medical imaging such a great idea? It didn't work out too well for Dr David Banner :P

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Iggy, that's really interesting! Also a nice illustration of how risky it is to use a theory far outside the range it was originally developed to work in. Some other effect might be significant, but not accounted for in your calculation...

 

But seriously, we think quartz lenses are pricey; imagine if our lenses had to be 24K gold.

 

Maybe plutonium would work...

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I went looking for these web resources and I'm having trouble finding anything that doesn't refer back to the same work you quoted, from 2012. Also, the claimed result from 2012 was that the refractive index of silicon for gamma rays was n=1.000000001, which obviously is not enough to make a lens in itself. The original author of that 2012 result doesn't seem to have followed it up either, and that was 4 years ago now. I hate to say it (because it would be really cool if true), but this is looking less convincing the more I check into it.

 

Hmmm. Very good points.

 

However, the sudden absence of any follow-up, soon after an initial finding, should neither be a mark for, nor against it. It is fallacious logic in itself, to infer that some study is false, just because it suddenly goes "silent" for years, afterwards. There could be any number of reasons for this, be they economic hurdles / difficulties, or perhaps even socio-political and/or corporate involvement. (Read into this as "conflicting interests", and the subsequent manipulation / influence at work. Precious metals do, after all, have the sort of following that are highly-manipulated by corporate interests. The same goes for oil, and diamonds.)

 

Not that I am claiming those other possibilities to be the case, mind you. I am simply stating that when follow-up studies / peer-review are "M.I.A.", there could be any number of reasons for this, and not necessarily because the initial finding was in error.

 

In fact, that any additional follow-up after the initial report is strangely missing - be it in support of, or in refutation of - is very suspect in itself. (You would think that if the research was falsified or misrepresented in some way, then some other scientists would be quick to publish a scathing peer-review to the contrary, right? And yet, nothing. Whether for it, or against it. Think about that.)

 

For now, I have adopted the measured and guarded position that ... until or unless additional peer-review on the matter is released ... then the most plausible explanation (in my humble logical inferring) points to economic hardship. (Exceptionally high expense for procurement and ongoing testing, especially for a fledgling science that very likely has little grants / sponsorship for adequate funding for the time being, so it has to crawl along, rather than walk or fly.) Thus, a "stalled" field, if you will. For now, anyway.

 

This is not to say that we shouldn't be skeptical. And yet, as stated, the absence of any additional follow-up - either for or against the initial release, should not be assumed as an indication of error / falsification, in itself.

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Lead fishing weights are safe enough to handle as long as you wash your hands.

 

When I referred to potential toxicological dangers in prolonged / extended "handling" of lead, I didn't necessarily just refer to direct contact. I was also referring to other forms of secondary exposure. (Lead does emit air-born particulates, or "fumes", over time. It's a soft enough metal to do so, thus surface oxidation / decay can release substantial fumes.) Such is the case, for instance, with older homes which once used lead-based paints, where ongoing inhalation of lead fumes were far more potentially dangerous over the long run than any single one-time direct contact with the hands.

 

So, there's more to what I was suggesting, than meets the eye. (Lead and gold both being soft metals, the slow-release of fumes is not unusual, especially when the medium is constantly exposed to fluctuating temperature changes and variable humidity over a longer period.)

 

It's the same situation with cigarette smoking. Even if one does not smoke or chew tobacco themselves, a prolonged "second-hand" exposure (through inhalation by proximity) can be even more health-detrimental than direct exposure.

 

Lead fishing weights spend most of their time either inside of a tackle box with a lid on it, or dunked in the water. They don't spend much of their time being held close to your face, near your nose and eyes. Lenses, on the other hand ...

 

(Speaking of which, why holding some of those vintage thorium-infused lenses close to your head for extended periods - such as older Asahi / Takumar prime lenses - could have potential consequences, in terms of low-grade radiation poisoning. There is still much public debate over this, of course. However, I simply wanted to raise this point, as somewhat related, even though it deals with a whole different type of exposure.)

 

In any case, when it comes to toxicology, 1. proximity of use (how close to the subject, and which parts of the body exposed, especially orifices with easier access to internalization), 2. multiple processes of exposure (not just touch, but other processes of absorption such as inhalation) and 3. sustained period of exposure, are the most vital of parameters to consider ... while 4. overlapping them. (How they combine, for a synergistic effect.)

 

Not to split hairs. Haha. But that's what I do. Split hairs. :D

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EDIT: Come to think of it, now that I thought about it a bit long (pertaining to the strange absence of due follow-up / peer-review, whether against or for it) ... I have come to suspect that if the technology is indeed viable, then it was diverted towards military use, for the time being.

 

Experience has shown me, time and again, that with nearly every emerging technology ... the military gets it, first. Then, the medical / industrial fields (once the tech has been declassified). Then, the consumer, finally. (The "bottom feeder.")

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Yeah, economics could be it, Iggy, but my personal null hypothesis for new papers is that new claimed effects probably don't exist. Something like half of new papers turn out to be wrong. So I am a "glass half empty" kind of guy.

 

At any rate, even if it turns out to have some payoff down the line, this is very much in the basic science stage, not the engineering stage.

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Yeah, economics could be it, Iggy, but my personal null hypothesis for new papers is that new claimed effects probably don't exist. Something like half of new papers turn out to be wrong. So I am a "glass half empty" kind of guy.

 

So, in other words ... assume as a false claim, until shown otherwise. I do find that admirable. It's certainly better to err on the side of skepticism, rather that blind acceptance. I'll commend you for that.

 

With me, on the other hand, my default position (in the face of an initial claim, without additional backing up), is neither half-full nor half-empty. But rather, the "empty slate" position. (Assume nothing, as if you were to start all over, with no strong assumptions in either direction). My position would be a more open mind, but overall it does remain guarded, nonetheless.

 

But, perhaps, leaning a bit more on the skeptical end wouldn't hurt.

 

It's just that I have seen my fair share of flawed (and rather dogmatic) thinking, in which excessive skepticism (when too heavy-handed) can ruin scientific pursuit, too. So, perhaps, a moderate leaning to the side of skepticism, of an otherwise centrist position, then? ;)

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A quick look with Google shows the researcher, who led the group doing the work and publishing the paper, retired mid 2012 ... He is now Professor Emeritus. The follower on his chair at the LMU München has a different research focus.

 

So 1.) there has to be a researcher, who wants to follow up, then 2.) she/he has to find funding, these type of experiments are just the opposite of cheap, then 3.) she/he has to put together a group, then 4.) they need a gamma source and have to built the required equipment, then ....

 

Assume, all this takes some time. By the way, one of the authors seems to be involved in building up a new labarotory for similar kind of studies in Romania.

 

With respect to lead: This has a quite low melting point ...

 

There are some reviews regarding the theoretical part and explanations (unfortunately, one needs to pay for the papers).

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I wonder if anyone has looked into making lenses from compounds containing metastable isotopes. Since the index of refraction (n) is a result of temporary capture and release of nonresonant photons by matter and in the gamma region such photon captures are nuclear in origin. It might follow that elements that are capable of capturing a gamma photon of a particular energy should have an appreciable capture cross section for nonresonant energy photons as well. This would be analogous to otherwise NUV/vis transparent media having stronger n for wavelengths approaching resonant ultraviolet transitions.

 

Of course such a lens medium would also be the lasing medium for a gamma ray laser so there's your military tie in.

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  • 4 years later...

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