Femtosecond Lasers Used To Color Metals

Maximum Prophet writes "An optics professor and a postgrad have developed a way to use ultra-short pulses of laser light to etch nano features into the surface of metals so that they can absorb or reflect specific wavelengths of light. This is very similar to the way that butterflies get the color in their wings."

Comments

WOW!

[JoshEanes]

wow, butterflies use high energy lasers to get the color on their wings!?!? now, we have to worry about lasers in the hands of the insects...

Re:WOW!

[jollyreaper]

wow, butterflies use high energy lasers to get the color on their wings!?!? Not to self: don't fuck with butterflies.

Re:WOW!

[Rei]

Why did you link an article that argued against your point? The article says that the bright color of the upper sides of the wings is due to interference, and that only the dull underside is due to pigments.

Most of the colors in my parrot are due to the same diffraction effect from the spacing of the barbs in his feathers. There are two interesting things you can observe. One, when you get him thoroughly soaked in a shower, he becomes all dull except for the yellow feathers on his head (which are pigmented); it's a pretty dramatic color change. Two, when the tips of a feather passes in front of another feather, you get neat Moire patterns.

Re:WOW!

[Zymergy]

There is some confusion here, Please first refer to this: http://en.wikipedia.org/wiki/Additive_color and to this http://en.wikipedia.org/wiki/Interference_filter
Actually, butterfly wing-scales are the color of the underlying wing cells that produce the scales (and not blue, etc..) The scales are actually not blue, they are probably the color of butterfly skin cells.
The intense powder blue colors observed in butterfly scales are caused by Optical Interference Filter phenomenons in the microscopic slits in the surface of the scales *only* and not from a pigment or dye. Think of it as a mirror that adsorbs light in all optical wavelengths and reflects only the shades of blue observed. If you were to shine light of different wavelengths like pure green or red, the wings would be appear dark or mostly black as they absorb wavelengths of light that are not those specific to those shades of blue light they reflect.
Traditional colors (in most things we see daily) are caused by pigments and dyes (subtractive color) or from CRT/LCD/Plasma display RGB techniques (additive color).
This 'new' technology using "Femtosecond Lasers" creates precise cuts in the surface of metals (or other substances), to create these precise interference pattern slits to produce brilliant colors. These slits act as a slit interference light reflector/absorber as they brightly reflect specific wavelengths like a selective mirror and adsorb others. This method is vastly more efficient than colored subtractive filters and therefore produce colors far more intense than any pigment or dye could produce.
All butterfly and moth scales are made of non-living insect cuticle. Insect cuticle comes from epithelial cells and is made up of chitin and protein. These Chitins and Proteins are not necessarily colored or pigmented. Their observed 'colors' virtually all come from their nano-scale *structures* which have microscopic optical interference reflectors/absorbers. Some insects use these 'scales' to very efficiently absorb light to stay warm in sunlight and the light reflected is very brilliant and is essentially a mirror to particular wavelengths.

The important thing FTA is that now mankind has learned how to use lasers to be able to modify the surface of metal substrates (of whatever native 'color') to adsorb and reflect specific wavelengths of light in the visual range. This can be used to make better coatings and even better camouflage. The USAF already uses similar technology in their "stealth paint" with radar-adsorbing interference filtering "stuff" in the paint itself (as well as the shape). This new technology reads to me to to be a good step in the direction of daylight stealth and camouflage, but just like the butterfly wings. Once touched or structurally affected, the surface structure changes and so does the color absorption/reflection. This is why it is very necessary to carefully clean stealth aircraft just before missions, otherwise combustion particles, dust, etc.. can reflect radar and defeat some of the paint's stealth properties. This would have a similar optical effect on the "Femtosecond Laser-colored Metals" referred FTA.

Re:WOW!

[BytePusher]

I don't know about your butterflies, but my butterfly emits light! Take that you insensitive clod!

Re:WOW!

[BotnetZombie]

Not to self: don't fuck with butterflies
Double negative... Must - not - not - imagine - this - scenario

Re:WOW!

[ozbird]

I think you meant to link to the diffraction grating article.
Diffraction gratings using parallel lines to produce the colours; interference filters using layers of differing refractive indices.

Re:WOW!

[Rei]

[quote]Color has exactly one definition: the particular hue, not the intensity thereof. The color is determined by the color of the powdery scales.[/quote]

The article says nothing of the sort. In fact, it says just the opposite: "Blue light has a wavelength range from 400-480 nm, and is the only wavelength that is interfered with constructively by the slits of the morpho, which are 200 nm apart."

Your article completely undercuts your argument.

Hmm good bye automotive paint??

[moogied]

Perhaps the end to automotive paint?? Just throw clear coat over the chagned metal...

Re:Hmm good bye automotive paint??

[psbrogna]

It might be cheaper given the cost of disposing of hazardous waste associated with conventional painting processes.

Re:Hmm good bye automotive paint??

[onion2k]

Automotive paint isn't just used to make your car look pretty - it's also a protective coating to stop it going rusty.

Re:Hmm good bye automotive paint??

[JeepFanatic]

I could see this for high end vehicles where people would be willing to pay the premium for a car who's "paint" will never fade.

Re:Hmm good bye automotive paint??

[Sandor at the Zoo]

Once you have the equipment, it just takes electricity. No need to buy paint, dyes, etc. on an ongoing basis. And according to the article, it's part of the metal, so it doesn't flake or rub off.

Re:Hmm good bye automotive paint??

[djlemma]

I have to wonder how difficult it would be to rub off the outer layer of the metal that's causing the wavelength modifications.. The article implies that the laser is modifying the metal at an atomic level, and I can't imagine it'd be too tough to scrape a few atoms off the surface of an aluminum body panel. What happens when a bird poops on the hood of your laser-colored car? Or worse, when some road tar gets splattered onto your front bumper. Normally, cleaning these up involves solvents and scrubbing, and I don't imagine that bare metal would withstand that combination all that well over time.

I, for one

[Malevolent Tester]

Welcome our new femtosecond laser wielding butterfly overlords.

Re:OK, I didn't read the FA yet....

[JeepFanatic]

Are they ill tempered?

Neat!

[Rizzen]

As an artist I find this highly interesting. I'm always looking for new mediums to work with, and I certainly hope this becomes easy enough to work with where I can experiment with it. I'm sure it would open up a whole host of new ideas for creative avenues.

Oblig. XKCD

[Anonymous Coward]

What a coincidence http://www.xkcd.com/378/

Sure it was the butterfly

[techpawn]

No one EVER suspects the butterfly...

A novel way to mark items for identification.

[TheLazySci-FiAuthor]

I wonder if this will work outside the range of visible light: up into ultraviolet or down to infrared wavelengths.

It might be a novel way to unobtrusively mark equipment or vehicles with permanent serial numbers or some kind of identification method for recognition by, say, machine vision, but which would not be visible to the unaided eye.

For robots to begin work in our everyday world, I feel that at first they are going to need some special markers around the house and office to help them recognize important objects more easily - this could be a very efficient and elegant way to accomplish just that.

Re:A novel way to mark items for identification.

[DerekLyons]

It should work in a variety of wavelengths. For 'house and office' use however, it boils down to two question: 1) how many common materials will take the markings (looking around my house and office, I see little metal and most of that is painted*), and 2) will the marking remain visible under a layer of dust (within a few hours of cleaning, you'll start to accumulate more - even if won't be visible to the naked eye for a day or two)?

*And how well a given metal accepts these markings will depend heavily on its crystal structure.

Colour me cynical

[GauteL]

.. but when I see things like "professor and a postgrad have developed", I assume that the postgrad did all the work and the professor took most of the credit.

Re:Colour me cynical

[mea37]

Careful saying things like that around the professor, or he will indeed colour you cynical. Using a laser.

Re:Colour me cynical

[Speare]

This argument is like the quarterback vs the coach.

While the postgrad may have done 99.9999999% of the annoying and tedious labor-intensive development of the concept, it is often the case that such partnerships start with a short conversation in a hallway, where either one of them could rightly claim to have spawned the insightful flash that led to the exercise in the first place, and neither one of them could rightly deny the claim of the other. Add that to the fact that the lab is provided by the professor's tenure and grant-gathering capabilities, and you really can't say that the professor isn't entitled to being listed prominently.

Re:Colour me cynical

[fishybell]

I asked by dad, a tenured professor / associate dean at the local university, and he said it depends on the professor. Most professors, and all the good ones, are in it for the knowledge and the spreading thereof. Any papers he publishes have the grad students listed first (by order of work done on the project) and his name last. The scientific journals know that the professor's name is last (and of course, followed by the telling doctoral title) as most professors want to give the credit to those who need it most; the students.

Most tenured professor, and a good deal of tenure track professors aren't vying for personal fame, they're vying for good results. They want their students to succeed in the industry. They don't need their own CV to glow extra bright unless they're planning on starting their own company using the technology. They also don't need the limelight as much as they work with two to four teams of students each semester on various grants. Some grants, of course, take significantly longer than a semester but each year the professor's CV grows by pages while the students' are just getting into page two.

Say what you like, but most professors really aren't out to jilk the student, they're out to help the students.

Re:Colour me cynical

[servognome]

.. but when I see things like "professor and a postgrad have developed", I assume that the postgrad did all the work and the professor took most of the credit.

The postgrad probably did all the labor, but the professor probably came up with the idea, provided guidance, and secured the funding. Being a grad student is just like being an apprentice in any other walk of life.

taste the rainbow

[davidwr]

I ate a CD once. It tasted nothing like Skittles.

Re:Butterflies with lasers

[CubicleView]

Offtopic I know, but I just googled The Gloom Wing Moth because I've no idea what you're on about and your post was the only hit I got. Google seems to have Slashdot in pratically real time these days.

Hey! Where's the

[wiredog]

"whatcouldpossiblygowrong" tag! Come on! They're giving lasers to butterflies!

Re:Butterflies with lasers

[Binestar]

*I* googled Gloom Wing Moth and I got his post, your post, this post and the post you're going to make in reply to it. Google is faster than real time today.

New upgrades to "Shark Army(tm)" project

[DrYak]

wow, butterflies use high energy lasers to get the color on their wings!?!?

Forget the sharks !
Let's make an army of butterflies with freakin' femto lasers on their head and take over the world with them.

poll

[Thornburg]

Quick Poll:

Did the poster and/or editor intentionally make the ambiguous statement about butterflies, knowing that it would lead to a discussion 80% about laser-wielding butterflies, with real article-related content left to battle with the usual jokes/OT garbage/etc for the remaining 20% of comments?

Possible Answers:

() Yes, and it's awesome.

() Yes, and it sucks.

() No, but it's awesome.

() No, and it sucks.

() CowboyNeal forced them to.

Re:Butterflies with lasers

[ThreeGigs]

Gloom Wing Moth

Phew!

Stop playing with the timestream folks, our universe was almost pinched off in a temporal loop.

hmm

[sonoronos]

Call me a skeptic, but I find it hard to believe that surface etching can cause the photon absorption characteristics of the material to change, a property which has more to do with the atomic structure of the material than its gross features. This leads me to believe that the color properties of the material are probably due to anisotropic reflection - meaning that the difference between "light" and "dark" between frequencies is the difference between "reflective" and "matte". Therefore, the intensity of the color produced by this method is limited by some mean function of available light, viewing angle, and the minimum feature size - which is limited by the material and not by the laser being used. Therefore, I would expect a material like gold, which exceptional stability to have the most intense colors providable by this method, which is a bit ironic, considering the subject of the article. I don't see General Lee Orange "painted by laser" onto a 1969 Dodge Charger any time soon.

Re:hmm

[OneSmartFellow]

OK, you're a skeptic. Index of refraction is everything.

Coloured MacBook Pro?

[Midnight Thunder]

Hmm, I wonder whether I could get him to apply the process to my MacBook Pro? If he manages to get the technique to colour metal in industrial quantity that could be amazing.

Stealth Applications

[WinCheers]

If he can figure out the right permutation to absorb radar or have radar waves cancel themselves out, then the military may be interested.

Prior Art

[PPH]

Paint.

Muhammed Ali vs the CD

[sm62704]

tastes like a rainbow, stings like a bee

uh huh...

[r00t]

Sure. Your "shoulder" or "arm". Riiiigh...

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8====D

Not that there's anything wrong with owning a p3n15 b1rd.