Doctor Light

Doctor Light was a Justice League member after the Thanagarian invasion. Her powers are based on light manipulation.

Background information
Doctor Light's origin in the comic books are closely tied to the DC comics event Crisis on Infinite Earths so it is unlikely that her DCAU backstory is the same. In the comic books her name is Kimiyo Hoshi, she was an antisocial supervising astronomer studying the effects of the Crisis with other male astronomers, disgusted by the men's fear she told them to leave so she could study the events alone. The Monitor knew the evil Anti-Monitor was absorbing yet another positive-matter Earth with his antimatter cloud (the overall plot of the Crisis series) and in order to tip the scales for the heroes of the positive universe, the Monitor sends a devastating beam of energy from the star Vega to Earth, which strikes the observing Kimiyo, leaving massive destruction in its wake. Granted the power of photonics and the name Doctor Light, Hoshi is assigned by the Monitor to guard one of the vibrational forks needed to save the Earth. After seeing the sacrifices made by other heroes Kimiyo realizes how selfish she has been and resolves to change. She is instrumental in the final battle with the Anti-Monitor and after the Crisis is over she become a superhero.

The scene in "Flashpoint" where Doctor Light goes and picks up Superman outside the Watchtower hints at a scene in Crisis on Infinite Earths where she carries an unconscious Superman to safety.