A Canadian company fights counterfeiters by implementing one of nature's most sophisticated structures: a butterfly wing.
By: Ofir Marom
In the tropical forests of Latin America you can see the blue morpho butterfly (Blue Morpho), one of the largest types of butterflies in the world, whose color in the upper part of its wings is bright and bright blue. The mechanism that creates the intense color is called "structural coloration". The light that hits the butterfly's wing is refracted because of its unique structure and is reflected back at certain wavelengths.
In general, the color obtained depends on the structure of the surface and the angle at which the light hits. In the case of the morpho butterfly, the wings are covered with scales made of chitin, which are arranged in a unique zig-zag pattern. Researchers from Simon Fraser University in Canada have found a way to give ordinary surfaces the color of butterfly wings. The trick is to artificially change their surface, by special stamping, which creates arrays of nano holes. The size of the holes in the pattern ranges from 50-300 nanometers in diameter, at intervals of 300-600 nanometers apart. By changing the geometry of the array of holes, you can choose the colors that will be obtained. The mold manufacturing process is based on technology accepted in the microelectronics industry. First, a pattern of the holes is made on silicon or quartz using an electron beam, similar to how computer chips are made. In the second step, using the template, a stamp made of nickel is produced, which is actually an array of protrusions, and which can be stamped on a variety of materials. The production of the stamp takes several hours - up to several days, but once the stamp is ready, it can be integrated into mass production processes.
The license for this unique technology was purchased by a Canadian company called "Nanotech Security Corp", which specializes in commercializing solutions and products in the field of security. The company claims that using this technology makes it possible, for the first time in the world, to implement five different security mechanisms in one stamp, from the simple level of an image, which can be seen with the naked eye, to the encoding of encrypted information, which can only be read with the help of advanced laboratory equipment. Thanks to the fact that special algorithms and expensive and sophisticated equipment are needed to produce these seals, it is difficult to impossible to imitate or fake them. These stamps are ideal for preventing counterfeiting of banknotes and bank checks, a problem whose damage to the world economy is estimated at about 600 billion dollars a year. As mentioned, this stamp can be stamped on a wide variety of materials such as: metals, plastic and glass, so it can be used to prevent counterfeiting of many consumer products. In the process of stamping the surface no ink or any other chemical substance is used, therefore it is possible to create a unique pattern even on medicines.
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Thanks Nissim. Comprehensive and fascinating information.
seeker
Opera houses have an acoustic system, which roars so that the sound from the stage is distributed uniformly among the hall's occupants. This system returns only frequencies that are important for listening to music.
cd is a compact disc. It has small dents on one long spiral. The distance between the spiral lines is such that a constructive struggle is created in different colors, depending on the viewing angle. That's why you sometimes see colors when you look at a CD.
The idea is that if there are several layers that reflect light, and the distance between the layers is an integer multiple of wavelengths then the same wavelength will be reflected more distinctly from the layers.
It is similar to the situation of rocking a child on a swing - if you rock him every time he returns to the peak of height then the oscillations will get stronger.
Thank you for the information.
What happens in opera halls, and what is a cd?
seeker
Note that it says that the distance between the holes is 300-600 nm. It is a field of visible light. This distance will cause constructive interference in the visible field. The same phenomenon exists in a puddle of water over which there is a thin layer of oil, CD, and also a pigeon's neck.
In the field of audio, the phenomenon occurs in opera halls.
How does the geometry or the distance between the holes determine the color? For those who understand - thanks.