Fast and "dirty" industrial applications with the separation capability of an electron microscope
The use of an electron microscope with nanometer resolution (resolution) is very common, but these instruments cost millions of dollars, and preparing a sample to view them is an exhausting task. This is a reasonable situation for laboratory work but impractical for industrial application: for example, rapidly scanning product samples for embedded microscopic identification marks.
A new type of holographic microscopy developed by David Greier, a physicist at New York University, and his colleagues may provide a solution. They started with a commercial Zeiss microscope and replaced the incandescent light bulb used as a light source with a laser. The laser that illuminates the sample and the light reflected from it create a two-dimensional interference pattern, i.e. a hologram, which is recorded by a video camera.
Scientists have been creating holograms of microscopic objects for decades, but extracting useful information from them has been difficult. And here lies the added value of Greier's invention: the team wrote a computer program that quickly solves the equations that describe how light is scattered by a spherical object. By extracting the values of some conditions hidden in these equations, the program collects information about the object that caused the scattering. The microscope with the nanometer resolution will allow researchers to follow particles floating in colloidal solutions (for example, nanometer-sized globules floating in a sample of paint) at a cost of about a tenth of the price of an electron microscope.
Greier hopes his device will provide, for the first time, a quick and inexpensive way to get a direct look at the particles at the heart of modern products. Imagine a bucket of paint or a jar of shampoo where every drop contains particles that code the course of its production: how it was produced, in which factory and when. "Something like a fingerprint," says Grayer. According to him, the microscope could just as easily read molecular messages embedded in drugs, explosives and other products.
More on the subject
A Vector-Free Microfluidic Platform for Intracellular Delivery. Armon Sharei et al. in Proceedings of the National
Academy of Sciences USA, Vol. 110, no. 6, pages 2082-2087; February 5, 2013. http://www.pnas.org/
content/110/6/2082.full
Fast Feature Identification for Holographic Tracking: The Orientation Alignment Transform. Bhaskar Jyoti
Krishnatreya and David G. Grier in Optics Express, Vol. 22, no. 11, pages 12,773-12,778; June 2, 2014.
Eyeglasses-Free Display: Towards Correcting Visual Aberrations with Computational Light Field Displays. Fu-Chung Huang et al. in ACM Transactions on Graphics, Vol. 33, no. 4, Article No. 59; July 2014.
Ideas from two worlds 2014: Scientific American Israel, April-May 2014; http://www.sciam.co.il/archives/7568
The article was published with the permission of Scientific American Israel
