Great article! These lenses (and/or these techniques for making lenses) might potentially find future uses in IC/Chip lithographic processes, and the like...

Great article! These lenses (and/or these techniques for making lenses) might potentially find future uses in IC/Chip lithographic processes, and the like... But, here's the key takeaway (for me) from this article: >"To its surprise, the team would later learn that the shift in focus stemmed not from the changing size or curvature of the lenses, but instead mostly from an alteration to their so-called refractive index." Now THAT is highly interesting! That is highly interesting in the manufacture of microscopic lenses. But, perhaps more interesting is IF (and it's a big word, "IF"!), IF this concept can generalize to other systems in Physics... To recap (on the most general level), we have beams of light (energy in the wavelength of the frequency band of visible light) having their focus changed (collimated and dispersed) via change in the materials' refractive index... So several questions: 1) Does the equivalent of a "refractive index" -- exist for materials for wavelengths of energy outside of the spectrum of visible light? (I'm guessing that there is... Reason: The material property of a refractive index for visible light -- should be the subcase of a more general principle in Physics...) 2) If a refractive indexes exist for other materials and for other wavelengths, then is it possible to change the focus (collimation/dispersion ability) of these other materials via similar methods to those used for the microscopic lenses in the article above? And/or other methods? 3) How does/would the above relate to the Inverse Square Law? (https://en.wikipedia.org/wiki/Inverse-square_law https://en.wikipedia.org/wiki/Inverse-square_law) 4) If #2 is possible -- then can the Inverse Square Law, for certain materials, and certain wavelengths of energy, be changed via those or similar methods? 5) Is the concept of Impedance (Electrical Impedance in the context of Electrical Engineering/Electronics) related to the alteration of an electrical refractive index -- and if so, how exactly? Anyway, great article! Fascinating and brilliant and highly interesting research!