“Seeing is believing” – or, in the science and engineering world, it is perhaps better phrased as “Seeing is understanding.” LIG Nanowise has been helping engineers and researchers “See More” with their super resolution white light microscopes and objective lenses. With their recent launch of SMAL AIR, a non-destructive, immersion free lens tailored for the advanced semicon industry, 2021 is looking to be an exciting year for Manchester (uk based) LIG Nanowise.

For those of you not familiar with microscopes, we can only see down to a certain size limited by a fundamental physical law called the optical diffraction limit. This sets a limit on the ultimate resolution you can attain with a standard microscope, even with a perfect setup. With current state-of-the-art optics, this can be around 250 - 350 nm (varies with setup and light source) and may require an immersion liquid to achieve.

LIG Nanowise have managed to break the 100 nm barrier with white light, in air, vacuum and with water/oil immersion. They have achieved this with their SMAL and SMAL AIR lenses (Super resolution Microsphere Amplifying Lenses) which have a typical resolution of around 80 nm. Dr. Daniel Lonsdale, CTO and acting CEO of LIG Nanowise continues, “This is an extremely exciting development, especially where we have achieved this in both air and vacuum. Bringing advanced optics together with materials to break traditional optical limits with a unique product has huge implications for us as well as throughout the engineering world, particularly in the advanced semiconductor space. Our best work yet shows features down to 50 nm. With white light, this is truly astonishing!”

This all started with a publication in Nature Communications showing 50 nm resolution (DOI: 10.1038/ncomms1211) using glass beads. Prof. Lin Li and Dr. Wei Guo took this discovery and started LIG Nanowise in 2014 to commercialise the capability. However, going from experiment to product has taken some hard work, especially where it concerns methods and materials to maximise usability criteria: working distance / field of view. The initial product “SMAL” was launched in early 2019 along with a high-tech microscope, the Nanoro-M, and required an immersion media to see such good results. Today SMAL can be used on other microscopes, whereas SMAL AIR currently needs Nanoro-M but allows a user to achieve the same quality of results but without immersion. It is worth noting that LIG plans to expand SMAL-AIR’s usability further in the near future.

Beyond super-resolution, there is also “super” magnification. Typical top-end objective lenses available today allow up to x100 to x150 magnification. However, SMAL and SMAL-AIR provide x230 – x240. This alone is a considerable enhancement above and beyond existing state-of-the-art technology. There is also evidence emerging to show that these lenses provide enhanced colour information from the white light source.

Several theories exist to describe how this imaging can be possible. First, there is the description based around evanescent waves being captured and amplified/converted into travelling waves, allowing access to the super-resolution information held in the near field. Second, there is a description based around super-resolution “photonic nanojets” that can reach feature sizes much smaller than traditional optical limits allow. Finally, whispering gallery mode theory has provided a third route to describe how the small features can be detected, transmitted, and observed.

Where it comes to applications, this has been a journey of self-discovery for LIG. Not all samples are suitable for investigation. However, we have some quite clear guidelines to tell which will and will not work; if it can be polished flat and will have high-contrast features, it is likely to get really good results. Steve Wright, Marketing Manager at LIG Nanowise continues, “We have two fantastic market segments that are really interesting right now: Semiconductors (wafers etc) and minerology relating to platinum group elements (PGMs). We have put quite a bit of work into these and seen some amazing results. With international interest growing and our message getting out there, we hope for a very exciting 2021.”

find out more at: www.lig-nanowise.com