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!

[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??

[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.

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.

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.

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.

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.