Solar sail

A solar sail is a structure that forms a method of propulsion, based on the reflection of photons.

Bajoran lightships were equipped with solar sails. It was discovered that these sails also made them capable of faster-than-light speeds and interstellar travel, due to the presence of tachyon eddies in the Bajoran system. The Bajorans used solar sails as early as the 16th century, and continued to do so until as late as the 21st century. 

Benjamin Sisko built a lightship that employed a solar sail for propulsion after a visit to Bajor, and took it out into space with his son, Jake, as a traveling companion. 

In the 23rd century, the chief engineer of the USS Yorktown (23rd century) attempted to use a makeshift solar sail to focus and absorb radiation from a nearby sun, with the hopes of generating power to keep life support systems online. 
 * It appears that solar sail technology utilized by Starfleet had advanced to a point where the sails could be used as an energy source and not just for propulsion.