The Surge Illumination on the Ars Arcanum of WoR is said to be the Surge of Light, Sound and various waveforms. We´ve already seen the manipulation of light to create illusions, and Pattern has said that Shallan could use sound to make her illusions talk for themselves, also possibly letting Shallan alter her own voice just as Pattern does. But these are only two uses of a power that should be able to control many different types of waveforms.
So my theory is that this Surge can manipulate mechanical and electromagnetic waves such as microwaves, X-rays, ultraviolet, and even maybe shock waves.Giving the Lightweavers and Truthwatchers more abilities that are less passive such as being able to manipulate these weaves to magnify shocks waves to create (small) earthquakes, use sound to shatter objects (like the thunderclasts rock bodies and the carapaces of voidbringers) by reaching the frequency that the atoms of the object vibrate, and microwaves to possibly communicate between Knights of the two orders or create heat to warm people or objects .
However even if this is possible I reckon it would only be seen by the time the Scadrians have FTL travel and visit Roshar, since now the Rosharans knowledge in physics seems not advanced enough for them to be able to access this part of the surge without just stumbling upon it.
Any thoughts?