Practice portal › Electromagnetic Waves › Uses of the Bands, and lambda nu = c
Asked in GSEB Board August 2020 · Uses and atmospheric effects
Idea: reshaping a cornea means taking off a very thin layer without heating what lies under it, so the radiation must be absorbed in the first micrometre and each photon must carry enough energy to break a bond outright.
Ultraviolet does both. The excimer laser used in LASIK works at about 193 nm, and corneal tissue absorbs that almost completely at the surface.
Its photons break the molecular bonds directly, so the material leaves as vapour and the surrounding tissue stays cool.
So ultraviolet rays are used.
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