Technology developed at the Technion enables real-time measurement of "ghost waves" - light waves trapped on surfaces
A breakthrough in microscopy: an innovative technology developed at the Technion enables real-time measurement of "ghost waves" - light waves trapped on surfaces. Technion researchers from the Viterbi Faculty of Electrical and Computer Engineering published the discovery yesterday in the prestigious journal Nature Photonics. The research was led by Prof. Guy Bartel, head of the Laboratory for Advanced Photonic Research, and doctoral student Kobi Frischwasser. Kobi Cohen, Shay Tsass, Yaakov Khair-Aldin and Shimon Dolev are partners in the article.
"Ghost waves" cannot be detected by standard microscopy methods because their energy flows on the surface and cannot break out towards the microscope detector. This is a basic physical principle that limits the resolution of a microscope to about half the size of a light particle.
The near-field scanning optical microscopy method was developed to discover these waves and has subsequently become a significant tool in the study of materials, light-matter interactions and biological samples. Such microscopes are able to overcome the same limitation and thus provide a high spatial separation capability down to less than a millionth of a millimeter. Near field microscopy methods have evolved over the years and today they also incorporate advanced methods based on shooting electrons at the surface.
The limitation on displaying images in real time
And yet, the near-field microscopy, as well as the electron microscopy that provides similar information, suffer from several shortcomings, the most prominent of which is the limitation on the presentation of the images in real time, A necessary ability to characterize the development-in-time of minor phenomena.
Now, in an article in Nature Photonics, the Technion researchers present a new research approach to near-field microscopy that allows, among other things, to face this challenge with the help of a wave mixing phenomenon in nonlinear optics (Nonlinear wave-mixing) - a fruitful field of research that originated with the invention of the laser in the years -60. By shooting a wide beam of light into the surface, the Technion researchers were able to reproduce fully the electromagnetic field of those ghost waves and even demonstrated the application of this technology in monitoring changes in this field.
According to the lead author of the article, Kobi Frischwasser, "The discovery happened when I was working on another project altogether - creating unique ghost waves using non-linear optics. During the work I realized that the creation process is reversible, that is, to the extent that such waves can be produced in a non-linear process, they can also be read into the microscope detector and thus essentially solve the same old problem of Surface wave mapping - in real time. "
"During the aforementioned process, light of different colors is created, which provides us with information about those waves that remained close to the surface," explains Prof. Bartel. "Compared to the other conventional methods, the new technique we developed does not require unique equipment - a sufficiently powerful laser source and standard optical components are enough. We believe that other institutions and bodies will join us in order to quickly translate this technology into commercial applications."
The research was supported by the Israel Science Foundation (ISF), the Russell Berry Institute for Nanotechnology at the Technion and the National Academy of Sciences (Adams scholarship for doctoral student Shay Tsass) and the OT scholarship (for doctoral student Yaakov Khair-Eldin), and was conducted in collaboration with the Sara and Moshe Center for Nanoelectronics Zisapel and the Photovoltaic Laboratory at RBNI (Russell Berry Institute for Research in Nanotechnology).
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