Molecularly bonded armor
From Wookieepedia, the Star Wars wiki.
Molecularly bonded armor was an immensely strong substance used in the Stars' End prison on Mytus VII. It was so strong it could hold of the barrage from an Imperial Star Destroyer's turbolasers. To create the armor, dense metals were softened or liquified by ion fusers. Then, as the resulting alloy cooled, it was bombarded by charged-particle vibrating waves. This dramatically improved the bonding strength of the molecules and gave the armor incredible resiliency.
