Mario Chemnitz, scientist at Leibniz IPHT and first author of the publication, explains the unusual effect as follows: «The fiber core is filled with carbon disulfide, a liquid chemical compound with a very high refractive index. (sciencedaily.com)
It has a high refractive index, which enhances its stability and ability to protect skin from the sun's harmful rays. (bluelizard.net)
The high refractive index of silicon makes optical structures the size of a fraction of the diameter of a human hair possible. (sciencedaily.com)