Plasmonics Anti-Counterfeiting Technology

This could be interesting:

NOtES exploits an obscure area of physics to accomplish its bright and sharp display, known as plasmonics. Light waves interact with the array of nano-scale holes on a NOtES display—which are typically 100-200 nanometers in diameter—in a way that creates what are called “surface plasmons.” In the words of the company, this means light “[collects] on the films surface and creates higher than expected optical outputs by creating an electromagnetic field, called surface plasmonic resonance.”


And security, surprisingly, is one of the major applications of these light-amplifying tiny holes. Compared with things like holograms, NOtES has a number of advantages. For one, the technology consists of nothing more than an array of tiny holes, which means it can literally be stamped into anything. Nanotech Security is in talks with the Bank of Canada, whose new plastic bills are a perfect candidate for security measures embedded using NOtES.


Using a physical stamp, Nanotech Security can imprint its minuscule holes into bills even after they’ve been printed, instantly transforming the area of the bill that’s been stamped into something that resembles a tiny LED. It’s just like the old-school printing process that yields embossed invitations and business cards, except that instead of pressing “save the date” into cardstock, a nickel stamp covered with nano-scale bumps presses corresponding holes into a material.

The results aren’t just visually crisp, they’re also good for keeping things top secret. That’s because the NOtES process yields a surface that reflects light from ultraviolet all the way into the far infrared, or wavelengths outside what we can see, but which can easily be read by machines. This opens up the potential for NOtES to be used to create watermarks on bills that counterfeiters can’t even see.

Anti-counterfeiting technologies have a difficult set of requirements. They need to be cheap for legitimate currency printers, and at the same time expensive for counterfeiters. That this technology can encode unique serial numbers—or even digital signatures of unique serial numbers—onto paper currency would be a big deal.

Posted on December 19, 2011 at 6:48 AM28 Comments


Henning Makholm December 19, 2011 7:15 AM

Not to mention: an anti-counterfeiting technology must allow ordinary users of currency to verify it. Otherwise, what’s the point? A secret anti-counterfeiting feature may limit the time counterfeit notes stay in circulation, but it will not prevent counterfeiters from circulating them in the first place.

Dinah December 19, 2011 7:55 AM

@Henning Makholm: exactly what I was thinking. Anyone who makes fake IDs in my area of the USA knows that no one around here knows what a legit ID from across the country looks like; much less one from another country. And the flip side is: ~12 years ago, my friend from another state had a legit ID that no one believed because that state printed plain-looking text on flimsy card stock.

Neither were easily verifiable.

Clive Robinson December 19, 2011 8:00 AM


“anotech Security can imprint its minuscule holes into bills even after they’ve been printed”

I hate to ask the obvious question,

“what’s to stop these minuscule holes filling up the the dirt dust and detritus from ordinary everyday handaling, not to say cocaine from the slightly less ordinary usage…

One major requirment for security especialy “watermarks” is that they are “robust” in ordinary use, otherwise they tend to be pointless.

Clive Robinson December 19, 2011 8:17 AM

The statment,

“That’s because the NOtES process yields a surface that reflects light from ultraviolet all the way into the far infrared, or wavelengths outside what we can see…”

Is a bit misleading. Whilst it’s true that the technology can work down even into the radio microwave bands, it can’t do it across the entire spectrum at any one time.

Because it works by “resonance” in a similar way to a tuned circuit or optical cavity. Yes you can make different resonators in the same area (like the coloured dots in a TV screen) but you lose the “brightness” effect of the resonance.

ChristianO December 19, 2011 8:41 AM

What would signed ids accomplish?

I mean you can copy some legit ID and dupes could only be found if there was some online checking system that communicated position of IDs.

Though you could do that too without signing it.
Only difference… you can’t create IDs before there is a real note to it.

Ron Helwig December 19, 2011 8:50 AM

I still don’t see how stuff like holograms adds any value. Why can’t counterfeiters just use the same holograms that governments do? If its cheap enough for governments, why would it be any more expensive for counterfeiters? Are they really getting a great deal by buying in bulk from the hologram manufacturers?

Fred P December 19, 2011 9:21 AM

I think that the author of the piece exaggerates its potential applications; modern currency would seem to be a particularly poor application for this.

What happens when that bill gets washed? Are the holes the correct size or distance from each other after being washed and dried?

What happens when the relevant area gets folded – not once, but thousands of times? Are the distances between the holes still consistent? Are the holes still exactly the same size?

After, say a year and a half of regular use by coal miners, factory workers, and mechanics, are the holes still usable, or are they so clogged with dust and dirt that they’re useless?

That said, for something of value that is stiff, it sounds like it may be useful – a credit card, for example, might be a useful application – but there are quite a few anti-counterfeiting technologies that work well on credit cards that don’t on bills.

paul December 19, 2011 9:26 AM

I think this relies on secured items never getting into the hands of professional criminals. We’ve already seen how long hologram-embossing lasted as a security measure, and if this stuff is easy to print by legitimate sources, then it’s fairly soon going to be easy to print by illegitimate ones.

Worse yet, the very fact that it’s amenable to straightforward mechanical/electronic verification means that people could start relying on it exclusively and ignoring other signs of whether a bill is legitimate or counterfeit.

Rob December 19, 2011 9:28 AM

Clive, I think that’s the point. You make the watermark in the UV band, and the human eye can’t see it, but a machine can. It reflects all visible light, so you can’t even tell that the watermark is there just by looking at it.

Fred P December 19, 2011 10:10 AM

@Ron Helwig-

It’s the initial cost that’s quite the barrier to a lot of counterfeiters.

Most would-be counterfeiters are individuals or small, resource-poor groups. Any protection mechanism that’s easily recognizable, has a high initial cost, and low recurring costs, and doesn’t degrade much with use is a good general-purpose one.

Obviously, major counterfeiters, such as has been alleged of at least one government and several large drug cartels don’t have those problems, but reducing the effectiveness of small-scale counterfeiting has a significant impact. The large-scale ones (due to the number of bills they print) are more traceable – since currency gets to banks and federal reserves with some frequency – and presses are hard to move.

Here’s a pretty good paper on some of the subject:

“Both theoretical studies and the little empirical information we have suggest that high-quality counterfeiting is expensive and only effective when few counterfeits are passed relative to the amount of genuine currency in circulation. Producing high-grade counterfeits requires access to presses, inks, and high-grade paper.”

NobodySpecial December 19, 2011 10:19 AM

@Ron Helwig – the idea of holograms is that they are ‘impossible’ to copy photographically and relatively difficult to manufacture.

This means to make a fake hologram you have to re-draw the original and they need to be made by the same sort of high tech (and therefore limited) kit that makes the government ones – the idea is simply that your local printer shop can’t make copies easily.

Of course soon, enough unscrupulous outfits buy hologram printers that people making fake copies of Windows can also add fake holograms – it’s an arms race

The drawback of adding clever authentication features like holograms or SPR films is that people don’t really check – a customer just looks at a DVD box thinks “shiny hologram = genuine” and buys it with less scrutiny than they would give a bank note.

The more new and visual the technology the less people will actually examine it.

NobodySpecial December 19, 2011 10:21 AM

ps. About 20years ago UK banks started adding holograms to credit cards. The image one bank chose was William Shakespeare.

We had one manager who was rather balding and looked not unlike the famous bard.

A visiting American saw their credit card and was really impressed at the level of technology that allowed banks to print holograms of the customer on each credit card !

Andrew Gumbrell December 19, 2011 10:45 AM

“watermarks on bills that counterfeiters can’t even see”
I guess that means nobody can see them, then.

HerpDerp December 19, 2011 11:39 AM

For people asking about counterfieters duplicating production methods because of cost, you haven’t thought about availability. Just because some material is cheap doesn’t mean it’s not regulated, or EXTREMELY difficult to get ahold of. Also, for those of you who think this fails in “paper” currency 2 things: 1) It’s not really paper to begin with 2) bills are moving away from the traditional cotton-paper blend. See the new CDN $100 bill for example:–canadians-to-get-their-hands-on-new-plastic-100-bills-today

The “dirt” point somebody brought up is kind of interesting. However, if these “holes” are too small even for light particles, how do you suppose dirt will get in there?

NobodySpecial December 19, 2011 12:10 PM

@Dirt – there is lots of ‘dirt’ in the air smaller than light – even diesel exhaust isn’t far off.
If you provide a ready made substrate with the correct chemical properties there is always something that will grow or adsorb onto it.

Daniel December 19, 2011 1:21 PM

Thanks Andrew that was exactly what I came here to say. If the government can figure out a way to see them, so can counterfeiters.

@Herpderp. Why doest the dirt have to get “in”. Perhaps the same confounding effect would be achieved if the dirt covers the holes, seeing how big it is relative to the holes.

HerpDerp December 19, 2011 1:55 PM

@Daniel. Ok, but I still don’t see a problem? Are you saying that it’s improbable a merchant wouldn’t think to simply wipe the dirt off/clean the thing before testing it? Especially in the case of a polymer bill like the one I linked above, this doesn’t seem like that huge a deal. I would agree that on a traditional bill these would likely be useless (what if the bill tears right through where the holes are?) I’m not trying to say the holes are a silver bullet, but when combined with other tech (ie: polymer bills) it seems like it has potential. I know that the “maker” movement is quite popular, and home manufacturing of all kinds of items has never been easier, but I’m not sure how practical it is to assume they can produce reliable products of a “nano” scale yet.

NobodySpecial December 19, 2011 4:15 PM

You can’t wipe the dirt out of a hole 100nm across. And even a 1/20 of a wavelength (2nm) film of dirt/chemical/etc on an SPR will completely change it’s optical characteristics. That’s why SPR is so wonderful for making chemical/bio sensors.

Scott December 19, 2011 5:13 PM

This isn’t anything new – microembossing like this has been used for years to produce CDs, holograms and the like from master plates as described. Most of the literature behind the surface plasmon concept is several years old so this looks like a stab at commercialization.

Many of the above comments are correct – without a surface covering material, skin oil etc. from handling will obscure the pattern, and of course it won’t work with paper.

Thomas December 19, 2011 5:17 PM

“That this technology can encode unique serial numbers — or even digital signatures of unique serial numbers — onto paper currency would be a big deal.”

So much for the anonymity of cash…

Fred P December 19, 2011 5:42 PM


The U.S. Dollar is a de facto currency for several nations. This means that its attackers are fairly broad, and under a number of regulatory regimes. For example, in some countries, counterfeiting U.S. currency is legal (source “In some countries, counterfeiting of foreign currency is not illegal, or counterfeits presented at banks or exchange offices are routinely returned to the holder or retained by the bank or exchange office.”).

So in the case of the U.S. currency no individual country’s regulatory scheme alone will prevent counterfeiting.

Your comment about Polymer bills is interesting, but I don’t know enough about them (folding properties, behavior when washed, tear resistance, etc.) to intelligently comment.


Every bill in my pocket has a presumably unique serial number.

Thomas December 19, 2011 7:37 PM

“Every bill in my pocket has a presumably unique serial number.”

Yeah… forgot about those. OCR is good enough so that a special machine-readable version isn’t really needed.

Still, you could put a whole bunch of these serial numbers on a bill to make things easier for people tracking money.

NZ December 20, 2011 2:54 AM

While metamaterials have many unique properties, I see several challenges:
(i) Surface plasmons are typically excited at metal-dielectric interface, so I don’t think paper-air or plastic-air is going to work, so we need a metal film (or metal coins).
(ii) Visible spectrum will be blocked by dirt and fat residue. I think using RF will alleviate this problem, but this method requires specialized equipment to check the pattern.
(iii) I suppose it will be possible to “reverse-engineer” the pattern using a scanning electron microscope and then make a fake stamp using some method of patterned growth or etching. While both SEM and MOCVD machines are quite expensive, they are more or less common. (And perhaps it is possible to make a fake stamp using some kind of lithography and etching).

Andrew Philips December 20, 2011 8:28 AM

How does one create a unique (per bill) digital signature out of a microstamp die?

Perhaps, they could use an alphabet and print in bar code, hex or alphanumeric?

How is this much better than writing on the bill with lemon juice?

Fred P December 20, 2011 8:43 AM

@Andrew Philips-
1) Anyone can get lemon juice at a nominal cost.
2) Lemon juice washes out (or at least I think it does).

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