Ablative Armor

The ablative armor hull plating has been in development for a number of years, though various related to materials availability, instabilities, phaser and torpedo resistance, and long fabrication lead times have prevented it's widespread use on front-line starships.

The armor works in two stages; in the event of a shield envelope disruption, phaser or thermal EM is first dissipated over the hull surface, and above an undisclosed threshold causes the molecular matrix to boil off at a controlled rate, carrying away a large fraction of the landed beam energy. In most cases, the boil-off creates a medium density particle cloud, which may help disperse the incoming beam.
The first active starship to use ablative was the USS Defiant NX-74205. After this vessel's armor proved itself in combat, and also due to the Dominion War, many starships currently in production incorporate ablative armor.