Tag Archives: nano optics

Observing nanostructures in attosecond time

German scientists have observed a phenomenon (light-matter interaction) that exists for attoseconds. (For anyone unfamiliar with that scale, micro = a millionth, nano = a billionth, pico = a trillionth, femto = a quadrillionth, and atto = a quintillionth.)  A May 31, 2016 news item on Nanowerk announces the work (Note: A link has been removed),

Physicists of the Laboratory for Attosecond Physics at the Max Planck Institute of Quantum Optics and the Ludwig-Maximilians-Universität Munich in collaboration with scientists from the Friedrich-Alexander-Universität Erlangen-Nürnberg have observed a light-matter phenomenon in nano-optics, which lasts only attoseconds (“Attosecond nanoscale near-field sampling”).

Here’s an illustration of the work,

When laser light interacts with a nanoneedle (yellow), electromagnetic near-fields are formed at its surface. A second laser pulse (purple) emits an electron (green) from the needle, permitting to characterize the near-fields. Image: Christian Hackenberger

When laser light interacts with a nanoneedle (yellow), electromagnetic near-fields are formed at its surface. A second laser pulse (purple) emits an electron (green) from the needle, permitting to characterize the near-fields.
Image: Christian Hackenberger

A May 31, 2016 Max Planck Institute of Quantum Optics press release (also on EurekAlert) by Thorsten Naeser, which originated the news item, describes the phenomenon and the work in more detail,

The interaction between light and matter is of key importance in nature, the most prominent example being photosynthesis. Light-matter interactions have also been used extensively in technology, and will continue to be important in electronics of the future. A technology that could transfer and save data encoded on light waves would be 100.000-times faster than current systems. A light-matter interaction which could pave the way to such light-driven electronics has been investigated by scientists from the Laboratory for Attosecond Physics (LAP) at the Ludwig-Maximilians-Universität (LMU) and the Max Planck Institute of Quantum Optics (MPQ), in collaboration with colleagues from the Chair for Laser Physics at the Friedrich-Alexander-Universität Erlangen-Nürnberg. The researchers sent intense laser pulses onto a tiny nanowire made of gold. The ultrashort laser pulses excited vibrations of the freely moving electrons in the metal. This resulted in electromagnetic ‘near-fields’ at the surface of the wire. The near-fields oscillated with a shift of a few hundred attoseconds with respect to the exciting laser field (one attosecond is a billionth of a billionth of a second). This shift was measured using attosecond light pulses which the scientists subsequently sent onto the nanowire.

When light illuminates metals, it can result in curious things in the microcosm at the surface. The electromagnetic field of the light excites vibrations of the electrons in the metal. This interaction causes the formation of ‘near-fields’ – electromagnetic fields localized close to the surface of the metal.

How near-fields behave under the influence of light has now been investigated by an international team of physicists at the Laboratory for Attosecond Physics of the Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics in close collaboration with scientists of the Chair for Laser Physics at the Friedrich-Alexander-Universität Erlangen-Nürnberg.

The researchers sent strong infrared laser pulses onto a gold nanowire. These laser pulses are so short that they are composed of only a few oscillations of the light field. When the light illuminated the nanowire it excited collective vibrations of the conducting electrons surrounding the gold atoms. Through these electron motions, near-fields were created at the surface of the wire.

The physicists wanted to study the timing of the near-fields with respect to the light fields. To do this they sent a second light pulse with an extremely short duration of just a couple of hundred attoseconds onto the nanostructure shortly after the first light pulse. The second flash released individual electrons from the nanowire. When these electrons reached the surface, they were accelerated by the near-fields and detected. Analysis of the electrons showed that the near-fields were oscillating with a time shift of about 250 attoseconds with respect to the incident light, and that they were leading in their vibrations. In other words: the near-field vibrations reached their maximum amplitude 250 attoseconds earlier than the vibrations of the light field.

“Fields and surface waves at nanostructures are of central importance for the development of lightwave-electronics. With the demonstrated technique they can now be sharply resolved.”, explained Prof. Matthias Kling, the leader of the team carrying out the experiments in Munich.

The experiments pave the way towards more complex studies of light-matter interaction in metals that are of interest in nano-optics and the light-driven electronics of the future. Such electronics would work at the frequencies of light. Light oscillates a million billion times per second, i.e. with petahertz frequencies – about 100.000 times faster than electronics available at the moment. The ultimate limit of data processing could be reached.

Here’s a link to and a citation for the paper,

Attosecond nanoscale near-field sampling by B. Förg, J. Schötz, F. Süßmann, M. Förster, M. Krüger, B. Ahn, W. A. Okell, K. Wintersperger, S. Zherebtsov, A. Guggenmos, V. Pervak, A. Kessel, S. A. Trushin, A. M. Azzeer, M. I. Stockman, D. Kim, F. Krausz, P. Hommelhoff, & M. F. Kling.  Nature Communications 7, Article number: 11717  doi:10.1038/ncomms11717 Published 31 May 2016

This paper is open access.

Vancouver (Canada) -based NanoTech Security and its tireless self-promotion

First featured here in a January 17, 2011 posting about proposed anti-counterfeiting measures based on the structures present on the Blue Morpho butterfly’s wings, NanoTech Security is the subject of a profile in the Vancouver (Canada) Sun’s Dec. 28, 2015 Technology article by Randy Shore.

They’ve managed to get themselves into the newspaper without having any kind of real news, research or business, to share. As is so often the case, timing is everything. This is a low news period (between Christmas and New Year) and the folks at NanoTech Security got lucky with a reporter who doesn’t know much about the company or the technology. When you add in low public awareness about the company and its products (you couldn’t do this with a company specializing in a well established technology, e.g., smartphones), there’s an opportunity.

Getting back to Shore’s Dec. 28, 2015 Technology article in the Vancouver Sun,

Landrock [Clint Landrock], the chief technology officer at Burnaby-based [Burnaby is a municipality in what’s known as Metro Vancouver] Nanotech Security Corp., has spun off his SFU [Simon Fraser University] research to found the firm, which is developing nano-optics for the global battle against counterfeiters.

Colour-shifting holographic images, used as counterfeit protection on many banknotes, use technology that has been around for more than 35 years and they are increasingly easy to reproduce. Talented hobbyists can duplicate simple holographic features and organized criminals with deeper pockets can reproduce more sophisticated features with the right equipment.

Nanotech Security hopes to take a quantum leap ahead of forgers.

The detail and colour reproduction possible in Nanotech’s KolourOptick are dramatically better than the holographic images used on banknotes.

“We can improve a lot on those, by making the image a lot brighter, have a lot more detail and make it easy to view,” said Landrock. “When you try to fake that, it’s much more difficult to do and when you see a fake it looks fake.”

“Right now, the fake holograms often look better than the real thing,” he said.

Tiny structuresWhat [sic] Landrock found on the wings of the Blue Morpho was a lattice of tiny treelike structures that interact with light, selecting certain wavelengths to create a bright blue hue without pigments.

This ‘origins’ story includes a business mastermind, Doug Blakeway, and the researcher (Bozena Kaminska) under whose supervision Landrock did his work. Blakeway provides a somewhat puzzling quote for Shore’s story,

“I love nanotechnology, but I really have not seen a commercialization of it that can make you money in the near term, [emphasis mine]” said Blakeway. “When this was initially presented to me by Bozena and Clint, I immediately saw their vision and they were only after one application — creating anti-counterfeiting features for banknotes.”

The three formed a private company and licensed the patents from SFU, which receives a three per cent royalty on sales of the technology created under its roof. …

I am perplexed by Blakeway’s ” … I really have not seen a commercialization of it that can make you money in the near term” comment. There are many nanotechnology-enabled products on the market ranging from coatings for superhydrophobic waterproofing products to carbon fibre-enhanced golf clubs to nanoscale chips for computers and components for phones to athletic materials impregnated with silver nanoparticles for their antibacterial properties (clothes you don’t have to wash as often) to cosmetics and beauty products, e.g., nano sunscreens, and there are more.

NanoTech Security’s recently released some information about their financial status. They must feel encouraged by their gains and other business developments (from a Dec. 17, 2015 NanoTech Security news release),

Nanotech Security Corp. (TSXV: NTS) (OTCQX: NTSFF), (“Nanotech” or the “Company”) today released its financial results for the fourth quarter and year ended September 30, 2015.

Strategic Highlights from 2015

Revenue increased to $5.2 million a 131% increase over 2014. Security Features contributed revenues of $3.1 million.
Gross margin improved to 43% up from 34% in the same period last year. The improvement reflects the increased mix of higher margin Security Features revenue.
Signed two banknote security feature development contracts. The contracts are with top ten issuing authorities to develop unique optically-variable security features for incorporation into future banknotes.
Strategic meetings with large international banknote issuing authority. The Company has been approached by a large international banknote issuing authority to deliver a large volume of Optical Thin Film (“OTF”), and partner with our KolourOptik™ technology. Management continues to devote a significant amount of time and resources in advancing these opportunities.
Private Placement. The Company completed a non-brokered private placement financing of $2.6 million in equity units at $1.00 each.
Signed an amending agreement related to the 2014 Fortress Optical purchase agreement. The amendment provides that 1.5 million of the 3.0 million shares held in escrow, pending certain sales milestones were released from escrow and the remaining 1.5 million shares were returned to the treasury. The overall effect of the amendment resulted in a gain of $1.5 million and cancellation of 1.5 million shares.
Demonstrated KolourOptik™ security feature on metal coins. The Company successfully applied nanotechnology images to metal coins in a production environment at an issuing mint.
Granted five new patents expanding the growing IP portfolio. Three patents relate to the Company’s next generation nanotechnology authentication features, and two provide increased protection for OTF.

I’m curious as to how much of their revenue is derived from sales as opposed to research funding and just how much money does a 43% increase in gross margins represent? (Or, perhaps I just need to get better at reading news about *companies* and their finances.) In any event, signing two contracts and gaining interest in applying the technology to metal coins must have been exciting.

This story goes to show that if you understand news cycles, have a little luck and/or know someone, and have a relatively unknown technology or product, it’s possible to get media coverage.

*’company’s’ corrected to ‘companies’.

The Danish ‘Mini-mouth and wine

Denmark is not the first country that pops to mind when there’s mention of a nanosensor that mimics what happens in your mouth when you drink wine but that’s where the device was developed. From a Sept. 17, 2014 news item on ScienceDaily,

When wine growers turn their grapes into wine, they need to control a number of processes to bring out the desired flavour in the product that ends up in the wine bottle. An important part of the taste is known in wine terminology as astringency, and it is characteristic of the dry sensation you get in your mouth when you drink red wine in particular. It is the tannins in the wine that bring out the sensation that — otherwise beyond compare — can be likened to biting into an unripe banana. It is mixed with lots of tastes in the wine and feels both soft and dry.

Researchers at the Interdisciplinary Nanoscience Centre (iNANO ), Aarhus University, have now developed a nanosensor that is capable of measuring the effect of astringency in your mouth when you drink wine.

A Sept. 17, 2014 Aarhus University (Denmark) press release (also on EurekAlert), which originated the news item, provides a general description of the sensor,

… To put it simply, the sensor is a kind of mini-mouth that uses salivary proteins to measure the sensation that occurs in your mouth when you drink wine. The researchers are looking at how the proteins change in the interaction with the wine, and they can use this to describe the effect of the wine.

There is great potential in this – both for the wine producers and for research into the medicine of the future. Indeed, it is the first time that a sensor has been produced that not only measures the amount of proteins and molecules in your mouth when you drink wine, but also measures the effect of wine – or other substances – entering your mouth.

The wine producers’ perspective is introduced (from the news release),

The sensor makes it possible for wine producers to control the development of astringency during wine production because they can measure the level of astringency in the wine right from the beginning of the process. This can currently only be achieved when the wine is ready and only by using a professional tasting panel – with the associated risk of human inaccuracy. Using the sensor, producers can work towards the desired sensation of dryness before the wine is ready.

“We don’t want to replace the wine taster. We just want a tool that is useful in wine production. When you produce wine, you know that the finished product should have a distinct taste with a certain level of astringency. If it doesn’t work, people won’t drink the wine,” says PhD student Joana Guerreiro, first author of the scientific article in ACS NANO, which presents the sensor and its prospects.

Better Understanding of Astringency

There are many different elements in wine that create astringency, and this makes it difficult to measure because there are so many parameters. The sensor turns this upside down by measuring the molecules in your mouth instead.

“The sensor expands our understanding of the concept of astringency. The sensation arises because of the interaction between small organic molecules in the wine and proteins in your mouth. This interaction gets the proteins to change their structure and clump together. Until now, the focus has been on the clumping together that takes place fairly late in the process. With the sensor, we’ve developed a method that mimics the binding and change in the structure of the proteins, i.e. the early part of the process. It’s a more sensitive method, and it reproduces the effect of the astringency better,” says Joana Guerreiro.

There are also some technical details in the news release,

Quite specifically, the sensor is a small plate coated with nanoscale gold particles. On this plate, the researchers simulate what happens in your mouth by first adding some of the proteins contained in your saliva. After this they add the wine. The gold particles on the plate act as nano-optics and make it possible to focus a beam of light below the diffraction limit so as to precisely measure something that is very small – right down to 20 nanometres. This makes it possible to study and follow the proteins, and to see what effect the wine has. It is thereby possible to see the extent to which the small molecules have to bind together for the clumping effect on the protein to be set off.

The technique in itself is not new. What is new is using it to create a sensor that can measure an effect rather than just a number of molecules. In this case, the effect is the dry sensation you get in your mouth when you drink wine. However, it is also possible to use the sensor to measure other effects.

Here’s a look at the Mini-mouth,

PhD student Joana Guerreiro has taken part in developing a sensor, which - by using nanoscience - can measure how we experience the feeling of dryness in wine. Photo: Lars Kruse, Aarhus University.

PhD student Joana Guerreiro has taken part in developing a sensor, which – by using nanoscience – can measure how we experience the feeling of dryness in wine. Photo: Lars Kruse, Aarhus University.

Here’s a link to and a citation for the paper,

Multifunctional Biosensor Based on Localized Surface Plasmon Resonance for Monitoring Small Molecule–Protein Interaction by Joana Rafaela Lara Guerreiro, Maj Frederiksen, Vladimir E. Bochenkov, Victor De Freitas, Maria Goreti Ferreira Sales, and Duncan Steward Sutherland. ACS Nano, 2014, 8 (8), pp 7958–7967 DOI: 10.1021/nn501962y Publication Date (Web): July 8, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall.

ETA Sept. 19, 2014: Dexter Johnson provides some insight into the field of ‘artificial mouths’ in his Sept. 18, 2014 posting (Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers] about the work in Denmark.