A Link to the Past
Ocarina of Time
In Ocarina of Time, light beams are found in the Spirit Temple and behind the Spirit barrier door in Ganon's Castle. Link can use either movable Mirrors or the Mirror Shield to reflect the light onto Sun Patterns.
The Wind Waker
In The Wind Waker, light beams are only found in the Earth Temple and in the grotto within the Angular Isles, shining through holes in the ceiling. Link can use the Mirror Shield to bend the light to multiple Mirrors, while Medli can use her Rito Harp. This light also cures Link when Jinxed.
The Minish Cap
In The Minish Cap, light beams are found in the frozen Temple of Droplets, shining through skylights which can be opened and closed. They are used to melt blocks of ice to free their contents, such as Keys. After beating one of the temple's three mini-bosses, Link will find the Flame Lantern which allows him to melt blocks of ice without sunbeams.