Remember the scene in Star Trek IV:The Voyage Home where Engineer Montgomery Scott divulges the formula for transparent aluminum to a manufacturer so the visitors from the future can get quantities of the material to use in bringing whales into space? Well, this isn't as fun or useful, but a group of Oxford scientists have created a version of aluminum that is transparent to extreme ultraviolet radiation.
The team used a FLASH laser to knock out a core electron from every aluminum atom in a sample without disrupting the crystalline structure of the metal, which caused it to appear transparent to UV. The FLASH laser, located in Hamburg, Germany, is a new source of radiation that's ten billion times brighter than any synchrotron and emits very short pulses of soft X-ray light that are more powerful than most electrical power plants.
The team focused that tremendous power onto an aluminum sample 1/20th the diameter of a human hair, rendering it transparent. Sadly, that effect only lasted 40 femtoseconds, but it's showing that high power X-ray sources can be used to create new forms of matter.