Light Beam

The Light Beam is a Luminoth weapon and one of Samus's beam upgrades. Samus Aran recovered it from Dark Agon Wastes during the events of Metroid Prime 2: Echoes. The Luminoth first experimented with the idea of overloading Dark creatures with the Dark Beam, and when that failed, moved on to the Light Beam, which proved to be a far deadlier weapon in their war against the Ing, due to their weakness to the light energy in Aether's atmosphere. As with other Luminoth-designed weaponry such as the Dark Beam and Annihilator Beam, this beam uses a limited amount of Light Ammo, requiring 1 Light Ammo to fire a Light Beam shot. When she has exhausted her supply of ammo, she can charge the weapon in order to fire a regular shot, so she can activate portals. The Light Beam is similar to the Plasma Beam of Metroid Prime and Metroid Prime 3: Corruption. The arm cannon uses the shape of the Wave Beam from Metroid Prime and the Nova Beam from Metroid Prime 3.

Uses
The Light Beam can activate dimensional rifts on Dark Aether and greatly damages Dark enemies, such as the Ing. The Light Beam can also open White Hatches. It also has the ability to energize Light Crystals and Beacons; their radius expands, and any Ing caught within is severely damaged or even killed. The Light Beam can be charged to fire the Lightblast, releasing several white-hot spheres in a scattershot fashion. These spheres will home in on locked-on targets, and set them on fire if applicable. The number of spheres depends on the time the beam has charged, ranging from 3 to 10. Regardless of the charge time, the Lightblast always costs 5 Light Ammo to fire.

Sunburst
Main Article: Sunburst

Once acquired from the Grand Windchamber, Samus can use the Sunburst, the Charge Combo for the Light Beam. Though it uses up 30 Light Ammo, as well as 5 missiles, it creates a slow moving sphere of light that burns passing enemies and incinerates them, making it useful for destroying slow-moving Dark enemies.

Metroid Prime 2: Echoes Instruction Manual
"This fires beams of light than can pass through enemies and set them on fire. It can be used to energise Light Crystals, and is effective against dark creatures. Charge it to fire a wide-dispersing Lightblast that will continually burn enemies. The Light Beam can open white hatches."

Trivia

 * Ironically, the Light Beam can only be found on Dark Aether, while its Dark counterpart can only be found on the light world of Aether. This may represent Yin and Yang, which is the balance of Good and Evil
 * This beam shares several qualities with the first Metroid Prime's Plasma Beam, including the projectile itself, it's low range, fire speed, and its tendency to light enemies on fire. Likewise, the Dark Beam shares qualities with Prime's Ice Beam.