Microspheric lens – new word in optical nanoscopy
Scientific centers and manufacturing companies specializing in nanotechnology need a high-performance tool that would provide resolution of less than 100–200 nm, be simple and cheap in operation, and not require high investment. Previously, none of the methods of microscopy met the entire set of requirements listed above, so the idea arose to create such a device, taking as a basis a traditional wide-field optical microscope. At the same time, the key task was to solve the problem of the diffraction limit, which limits the resolution. In 2011, the founders of LIG Nanowise Professor of Manchester University Lin Li and Dr. Wei Guo developed a method that initiated the use of microspheres to increase the resolution of optical microscopy. In 2013, they co-published an article in which proposed a method of optical nanoscopy using SMON (submerged microsphere optical nanoscope) microspheres placed into the water. In this method, the transparent microspheres located between the sample and the microscope objective serve as an optical amplifier and allow us to surpass the diffraction limit of the lens, increasing the resolution several times. The SMON method was implemented only in experimental laboratory studies, but using its principles, we developed a SMAL (Super Resolution Microsphere Amplifying Lens) optical lens, in which microspheres sized between 30–100 μm are used. SMAL provides a 400x magnification and has an equivalent aperture of 5.49, so the resolution of images can reach 50 nm. The distance from the lens to the surface of the sample during measurements is 1–2 μm.
The nanoscope is designed for non-contact optical measurements to obtain a color image of the sample. Measurements are performed in neutral white light from an LED source. The photodetector is an 8.8-megapixel CMOS camera with a resolution of 4096Ч2160. The sample is placed on a three-coordinate stage, which is positioned with an accuracy of 1 nm. The maximum size of the scanning area is 200Ч200 μm. The software performs automatic correction of aberrations and image stitching. Depending on the tasks to be solved, a SMAL lens or a conventional optical lens is used.
What are the application areas for the current version of the tool?
NANOPSIS M is a tool for the study of samples in materials science, microelectronics and other fields of science and industries where non-destructive measuring of micro- and nanoscale structures is necessary. The key advantages of the nanoscope are low cost compared to other devices with a similar resolution level, ease of use and maintenance, and high measurement speed.
What are the prospects for the development of the nanoscope?
So far we are only taking the first steps towards commercializing the technology of microsphere optics. I am sure that it has excellent prospects, and we can count on the support of investors and cooperation with major manufacturers of measuring equipment. In 2018, the first installations of NANOPSIS M will be performed. The future plans include the creation of a nanoscope for working with biological objects. We will also develop work with foreign customers, in particular, in Russia we are exclusively represented by the TechnoInfo Ltd.
Interview: Dmitry Gudilin